INTRODUCTION

Fiery inflammation in the bowel can be due to several conditions. In inflammatory bowel disease (IBD), gastrointestinal (GI) tract inflammation episodes are common. Crohn’s disease (CD) and ulcerative colitis (UC) are two IBDs differentiated by location and bowel involvement.¹ That’s a point to remember: that IBD is an umbrella term that includes CD and UC. In 10% to 15% of patients, the features of CD and UC are so similar that it is impossible to differentiate between them and misdiagnosis may result.^1,2 Besides the GI tract, both CD and UC also may be accompanied by symptoms outside the intestine, called extraintestinal symptoms.

 

DIFFERENTIATING CD AND UC

CD results in patchy ulceration of any portion of the GI tract (see Figure 1) from the mouth to the anus. It frequently affects the terminal ileum and colon, and bleeding is uncommon. Typically, patients experience pain in the lower right abdomen.³ UC, this continuing education’s primary focus, involves inflammation of the colon mucosa. UC often affects the rectum, referred to as proctitis, and bleeding during bowel movements is common. Typically, patients experience pain in the lower left abdomen. It may extend into the left (sigmoid) part of the pelvis or beyond the sigmoid, or include the entire colon, referred to as pancolitis.⁴ In UC, inflammation leads to edema, ulcers, bleeding, and electrolyte losses.

Figure 1. The Gastrointestinal Tract

UC is a chronic idiopathic relapsing/remitting condition (meaning it waxes and wanes) with interactions between the environment, immune system, gut microbiome, and a genetic predisposition to the disease suspected as causes.⁵  UC’s incidence and prevalence is increasing worldwide.⁶ From 1990 to 2017, its incidence increased from 3.7 million individuals to 6.8 million affected individuals worldwide.⁷ UC is incurable, so treatment goals aim to achieve rapid resolution of symptoms, mucosal healing, and clinical and endoscopic remission. An additional goal is to improve a patient’s quality of life (QoL).^6.

 

Individuals with this complex condition have a high level of disability and high healthcare resource utilization. Beyond medical management, 15% to 20% of patients with UC will require surgery. Compared to adults without IBD, adults with IBD experienced $11,029 higher direct costs per patient per year according to one report.⁸ Documenting this diagnosis in the pharmacy’s profile can help pharmacists and technicians screen for potential problems more efficiently.

 

Differentiating the two forms of IBD drives treatment. Both CD and UC present as similar repetitive episodes of GI inflammation and create significant patient burden. In CD, inflammation or ulceration commonly occurs in the ileum and colon.⁴ Outside of the intestine, CD may affect the esophagus, duodenum, or stomach, and gallstones may occur. In UC, extraintestinal manifestations may appear most commonly as inflammatory arthropathies (joint disease) and bile duct inflammation and scarring, but may include bone, eye, and skin involvement.^9,10 Although IBD’s incidence peaks at age 15 to 29 years, 10% to 15% of new diagnoses occur among adults aged 60 years or older.¹¹ Both forms of IBD are more prevalent among non-Hispanic White people than among people in other racial/ethnic groups.¹²

 

PAUSE AND PONDER: What support can you provide to a patient who tells you that wherever they go, their first action is to scan for the closest bathroom?

 

UC’S PATHOPHYSIOLOGY AND ASSESSMENT

 

The normal colon is five or six feet long and three inches wide. Its layers of circular and longitudinal muscles and tissues contract to move food and liquid forward. It wraps around the outside of the small intestine, has segments, and looks somewhat flat. A seam runs vertically down the middle so the segments bulge on either side of the seam. As UC becomes chronic, the colon becomes more rigid and short, leading to a pipe-like appearance.⁹

 

The most important risk factor for UC is a family history of IBD in a first-degree relative.¹⁴ Patients with disease extension to the left side of the colon, or extensive colitis, are more likely to need medication, undergo colectomy (removal of a portion of the colon), and develop colorectal cancer.¹⁵  Risk factors for colorectal dysplasia (abnormal that are not cancerous but can sometimes lead to cancer) or cancer include disease duration and extent, active inflammation, presence of a stricture (inelastic narrowing of a section of the GI tract), polyps, and family history of colorectal cancer. The bile duct may also become diseased in 3% to 7% of patients with UC.^15,16

 

UC’s pathophysiology involves defects in the epithelial barrier, defective immune response, the presence of leukocytes, and microflora imbalance in the colon.^17,18 UC’s inflammation deteriorates the epithelium, and exposure to certain intestinal microbes worsens the inflammation.⁹ Other immune-related factors that affect UC’s pathophysiology and the body’s response include tumor necrosis factor-alpha (TNF-alpha), numerous interleukins, and elevated immune globulin levels.¹⁷

 

Two measures are recognized in UC. Gastroenterologists and researchers tend to use the erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP) components of the Truelove and Witts criteria. Researchers frequently measure ESR and CRP before and during treatments as outcome measures. The prescribing information for anti-TNFs, JAK inhibitors, and IL-12/23 antagonists also include ESR and CRP measures. Table 1 illustrates UC disease severity measured by assessment in the modified Truelove and Witts criteria.¹⁵

 

 Table 1. Modified Truelove and Witts Criteria¹⁵

Parameter	Mild	Moderate	Severe
Bloody stools/day (n)	<4	4-6	>6
Pulse (beats/minute)	<90	≤90	>90
Temperature (T) °C (T°F )	<37.5 (<99.5)	37.5 – 37.8 (99.5 – 100.4)	>37.8 (>100.4)
Hemoglobin (g/dL)	>11.5	11.5 – 10.5	<10.5
ESR (mm/hr) [or CRP mg/l]	<20 (normal)	20 – 30 (<30)	>30 (>30)

°C=degree Celsius; CRP = c-reactive protein; ESR = erythrocyte sedimentation rate; °F = degree Fahrenheit

 

In the clinical setting, the simpler Mayo score (see Table 2) is used more widely than Truelove and Witts criteria.¹⁹ It reflects stool frequency, rectal bleeding, a physician’s global assessment, and a measure of mucosal inflammation at endoscopy, with a maximum score of 12. Clinical response in UC is defined as¹⁹

• a reduction of Mayo score by at least 3 points and a decrease of 30% from the baseline score, or
• a decrease of at least 1 point on the rectal bleeding subscale or
• a total rectal bleeding score of 0 or 1

 

Table 2. Mayo Score for Ulcerative Colitis^15,20,19

	Points
Mayo Variables	0	1	2	3
Stool frequency	Normal	1-2/day more than normal	3-4/day more than normal	5/day more than normal
Rectal bleeding	None	Streaks of blood with stool <50% of the time	Obvious blood with stool most of the time	Blood passed without stool
Mucosa (endoscopic subscore)	Normal or inactive disease	Mild disease (erythema, decreased vascular pattern, mild friability)	Moderate disease (marked erythema, lack of vascular pattern, friability, erosions)	Severe disease (spontaneous bleeding, ulcerations)
Physician’s global assessment	Normal	Mild disease	Moderate disease	Severe disease

Mayo score = sum of scores for each of the four variables (maximum score 12)

 

 

Beyond clinical response, clinical remission is a desired objective and is defined as a Mayo score of 2 or less and no individual subscore exceeding 1.¹⁹ Mucosal healing is defined as a mucosa subscore of 1 or less. Disease activity is a measure used to decide what treatments to prescribe. Mild disease activity is defined as scores of 3 to 5. Moderate and severe disease activity are defined as scores between 6 and 10 and 11 and 12, respectively.¹⁹

 

The clinician’s patient assessment must be global (all encompassing).²¹ During patient interviews, clinicians should inquire about extraintestinal symptoms, which may include joint, mood, ocular, oral, or skin changes. They should order laboratory evaluation for anemia and liver function abnormalities. Clinicians should explore QoL issues, such as impact on school, work, or personal relationships. Treatment plans should incorporate patients’ unmet needs and preferences. Exploring the need for social and emotional support, financial resources, and adequacy of patient education regarding their disease are important.²¹

 

Throughout treatment, it’s important to assess the patient’s clinical response and remission periodically. Clinicians should monitor cross-sectional imaging, specifically MRI, CT and ultrasound, and surrogate markers, such as fecal calprotectin (FCP; type of white blood cell that migrates to inflamed tissue) and CRP.^15,22 A sigmoidoscopy or colonoscopy is recommended within three to six months of initiating treatment to determine the level of suppression of the inflammation, treatment response, or the need to modify the treatment.²²

 

THE PATIENT’S JOURNEY

The journey through symptoms, diagnosis, and treatment to quell the fiery inflammation associated with UC can be long and difficult. In one study, one in four individuals with IBD reported GI symptoms to their primary care physician more than six months before receiving a diagnosis.²³ Of these individuals, 10.4% reported symptoms five years before receiving a UC diagnosis. Delayed diagnosis often results in disease progression, worsening tissue, and mucosal damage, surgery, colectomy, or colitis-associated cancer.  Patients with a previous diagnosis of irritable bowel syndrome or depression were less likely to receive a timely specialist appointment.²³

 

UC is vastly heterogeneous. Table 3 presents two cases with distinct disease journeys.

 

 

Table 3. Two Distinct Patient Journeys^24,25

UC Patient Case 1		UC Patient Case 2
9-year-old girl diagnosed after ileocolonoscopy reveals diffuse moderate inflammation		UC since age 18
Moderate clinical disease activity, Mayo score = 8		Symptoms included bleeding, severe pain and swelling in lower abdomen, gas, and nausea
Low hemoglobin, low vitamin D		Lifestyle: Undergraduate, lifeguard, swim coach
Oral corticosteroids started followed by dose tapering dose and mesalamine started		Daily regimen of oral medication, rectal suppositories, nightly enemas
At week 4, active disease remained		Symptoms worsened so → ED
IFX started at 10 mg/kg at 0, 2, and 6 weeks		Barely able to eat or drink, covered with rash and inflamed eyes
At 26 weeks with IFX, she remained in clinical remission		Incontinence in street, bus, and post office
At 1 year, she remained in remission		Acute diarrhea with each BM → became homebound
Follow-up flexible sigmoidoscopy demonstrated mucosal healing		At age 29, married → then 10 weeks of hospitalization without remission
		Agreed to surgical colectomy → difficult recovery, diarrhea, and intestinal blockages
		Finally exercising, back to work, and monitoring the quantity, texture, and timing of food. Remained on pre-surgical medications.

BM = bowel movement; ED = emergency department; IFX = inFLIXimab

 

UC affects many distinct populations. In the pediatric population with UC, unlike in adults, the clinical condition can present atypically with a more severe, early onset and continuous inflammation of the rectum and colon.^26,27,28 In these patients, clinicians should assess disease location and severity. One study indicated 62% of pediatric patients with UC from birth to age 5 years had extensive pancolitis, and 38% and 31% from ages 6 to 11 and from ages 12 to 18, respectively, had pancolitis.²⁷   Children can also experience rectal sparing (a normal/unaffected rectum) and limited distal disease.^26,28

 

To optimize management, enhance QoL, and minimize complications in all patients, continued patient engagement is important.²⁹

 

GOALS OF UC MANAGEMENT

 

The UC treatment guidelines recommend goals of therapy to include²⁹

• induction and maintenance of clinical and endoscopic remission
• maintaining steroid-free remission
• improving QoL, and
• preventing complications, hospitalizations and surgery.

Pursuing these goals can also contribute to minimizing cancer risk.^21,30,31 Long-term mucosal healing may reduce the risk of dysplasia.³¹

 

The Treat-To-Target Approach                                                         

UC is considered relapsing/remitting because it presents as relapses of symptoms and then periods of symptomless response and remission. Beyond symptom remission, a treat-to-target (T2T) approach focuses on^32,33

• minimizing disease activity
• reducing futures risks and
• reducing future relapses or complications such as ileal strictures (narrowing), fistulas, functional impairment, or colon cancer.

 

In 2015, the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) initiative recommended that UC treatment goals should address two targets: clinical and endoscopic outcomes.³² IBD experts recommend using measures of inflammation such as FCP.³²  FCP detects GI inflammation sensitively and is used to monitor disease activity and predict relapse.

 

PAUSE AND PONDER: Which UC treatments do you see in your practice location most often?

 

UC’s treatment options are plentiful and evolving. Pharmacy team members can collaborate with multidisciplinary professionals regarding patient care for UC. (See SIDEBAR). Pharmacists’ drug therapy and disease management expertise can promote individualized treatment decisions for these complex patients.

 

 

SIDEBAR: Working with the Multidisciplinary Team

Team collaboration can increase patient and provider education, enhance quality of care, and reduce disease burden, and morbidity. Many pharmacists don’t know how to introduce themselves to or work with multidisciplinary teams. Sometimes, team members from other disciplines will call with questions or concerns, and the call opens the door for regular communication. Often, however, pharmacy staff will need to take the initiative and introduce themselves. Here are four tips to working better with the UC care team.

• Ask patients if they are seeing a nutritionist, primary care provider, gastroenterologist, or behavioral health provider (for stress support). If UC is severe, inquire if they have a surgeon or know their radiologist. Record these providers’ names in the patient record and contact them when questions or concerns arise.
• Make the patient your ally and be your patient’s ally. When you educate patients well and show them your capabilities, they will report back to their clinicians.
• When you work with a patient who has UC, let the professional team members know. Sending a quick note to say that, for example, the patient’s adherence was poor and you discussed ways to improve it with the patient sheds light on possible non-response. It also makes clinicians aware that you have skills and you’re not afraid to use them!
• Don’t be afraid to make team members aware of issues like cost or availability of less expensive options. Often, prescribers have no idea that patients experience sticker shock when they fill their prescriptions.

 

TREATMENT

Medication is a mainstay of treatment for patients with UC. Prescribers may combine, dose-escalate, reduce, or discontinue medications, depending on the patient’s disease severity.

 

Traditional Treatments

When a patient presents with mild to moderate UC, the expert consensus is to start treatment with an oral 5-aminosalicylate (5-ASA; sulfasalazine, mesalamine, and diazo-bonded 5-ASA [the prodrugs, balsalazide and olsalazine, which convert to mesalamine]³⁴) with or without a rectal 5-ASA.^34,35 In many cases, rectal dosing improves symptoms; using a suppository, enema, or rectal foam applies the medication exactly where needed. Sulfasalazine, balsalazide, and mesalamine are similarly effective and safe.³⁴ Some patients will respond inadequately and may need to escalate therapy to systemic corticosteroids, immunomodulators (IMM), biologics, or other agents. If symptoms persist, it is important to rule out infection, optimize adherence, increase the oral dose, and add rectal 5-ASA if not yet prescribed.^34,35

 

Comparative efficacy studies are helpful to clinicians. One technical review of multiple drugs in mild to moderate UC compared rectal 5-ASAs (5-ASA enemas 1 to 4 g/day or 5-ASA suppositories 1g/day) to rectal corticosteroids (hydrocortisone enema 100mg/day, prednisolone enema 25–30 mg/day, budesonide enema 2 mg/day, beclomethasone 3 mg/day or comparable foam) in 13 trials.³⁶ In mild to moderate ulcerative proctosigmoiditis cases treated for two to eight weeks, rectal 5-ASAs were superior to rectal corticosteroids for induction of clinical remission.³⁶

 

Table 4 lists the broad categories of medications for mild, moderate, or severe UC and dosing information.

 

Table 4. Medications for UC^22,37-42

Category	Substance	Dosage
5 – ASA	Mesalamine     Balsalazide   Olsalazine   Sulfasalazine	2 – 4.8 g/day (oral) 1 – 2 g/day (rectal)   6.75 g/day (rectal)   1 g/day (oral)   2 – 4 g/day
Corticosteroids	Budesonide   Budesonide MMX   Prednisone   Hydrocortisone   Methylprednisolone	2 mg/day (rectal)   9 mg/day (oral)   0.75 – 1 mg/kg/day   100 mg IV 4 times/day   125 mg IV/day
Thiopurines Immunosuppressives	Azathioprine   6-mercaptopurine	2 – 2.5 (max 3) mg/kg/day   1 – 1.5 mg/kg/day
Calcineurin inhibitors	Cyclosporine   Tacrolimus	2 mg/kg/day IV   0.2 mg/kg/day
Anti-TNF agents	Adalimumab       Golimumab       Infliximab	160 mg wk 0, 80 mg wk 2, 40 mg wk 4, then 40 mg every 2 wks; may ↑ to 40 mg/wk SUBQ   200 mg wk 0, 100 mg wk 2, 50 mg wk 4, then 50 mg every 4 wks; may ↑ to 100 mg if pt>80 kg SUBQ   5 mg/kg wk 0, 2, 6, then every 8 wks IV
Adhesion molecule inhibitors (anti-integrin)	Vedolizumab	300 mg wk 0, 2, 6, then every 8 wks IV
Janus kinase inhibitor	Tofacitinib               Upadacitinib	5 – 10 mg/day (oral) First 8 wks: 10 mg twice/day 10 mg twice/day for 8 more wks if partial response Then 5 mg twice/day or 22 mg XR/day for 8 weeks; then evaluate   45 mg/day for 8 wks then 15 mg/day (oral)
Interleukin 12/23 antagonist	Ustekinumab	250 mg to 55 kg IV 390 mg if >55 kg – 85 kg IV 520 mg if >85 kg IV Then 90 mg SUBQ every 8 wks
Sphingosine 1-phosphate receptor modulator	Ozanimod	0.23 mg days 1-4, 0.46 mg days 5-7, then 0.92 mg/day (oral)

G = grams; IV= intravenous; kg=kilogram; mg= milligrams; MMX = Multi-Matrix System technology drug release; SUBQ=subcutaneous; wk= week

 

Sulfasalazine

If sulfasalazine is prescribed, 4 g provides approximately 1.6 g of 5-ASA equivalence.³⁴ Typical doses are 2 tablets 4 times a day.^37,43 In some cases, prescribers may initiate therapy with a smaller dose, (e.g., 1 to 2 g daily) to reduce possible GI intolerance and slowly increase as tolerated. They may also try enteric-coated sulfsalazine.^37,43 Sulfasalazine is commonly prescribed for individuals with UC and rheumatologic comorbidities.⁴³ Periodic monitoring of complete blood counts (CBC) and liver function tests (LFT) is recommended.

 

Sulfasalazine may be poorly tolerated due to adverse effects such as headache, nausea, diarrhea, and rash.⁴³ Additional adverse events with sulfasalazine include folate metabolism interference, male infertility, and rare cutaneous side effects such as Stevens-Johnson syndrome. Anemia, leukopenia, or thrombocytopenia are also possible. Pneumonitis and hepatitis have been reported.⁴³  Sulfasalazine is contraindicated if a patient has a sulfa allergy. Sulfasalazine tablets are a yellow/orange color; individuals who take it may notice an orange tinge in urine, tears, and sweat that can stain clothing and contact lenses. Auxiliary labels and counseling should emphasize drinking plenty of fluids, taking the drug on an empty stomach, and avoiding antacids.

 

Mesalamine and Balsalazide

Low dose mesalamine may be prescribed initially at less than 2 grams per day(g/d). Some patients need 2 to 3 g/d. Higher doses of 3 g/d or more may be required to induce remission.³⁶ Combining oral and rectal therapy may deliver a higher effective dose of 5-ASA to the involved area and lead to higher rates of induction and maintenance of remission. This approach may avoid escalation to corticosteroids or other agents.³⁶

 

Mesalamine and balsalazide are associated with rare idiosyncratic worsening of colitis.²² Rare interstitial nephritis may also occur. The prescribing information recommends periodic renal function monitoring. Olsalazine is generally less well tolerated than either mesalamine or balsalazide. Headache, nausea, diarrhea, leukopenia and hepatitis are possible. 5-ASA treatments should be avoided in pregnancy.²²

 

Steroids and Other Traditional Treatments

Corticosteroids, such as budesonide, are generally prescribed for a short duration or for induction of remission.³⁴ Some experts suggest prescribing oral mesalamine, balsalazide or olsalazine over budesonide because hepatic first-pass metabolism lowers budesonide’s systemic activity.^34,44 As the patient’s condition improves, withdrawing the steroids and reaching steroid-free remission (SFR) is important. Long-term corticosteroid use may lead to infection, diabetes mellitus, weight gain, insomnia, osteoporosis, or glaucoma.⁴⁵ Mood changes, cataracts and delayed wound healing are possible.⁴⁵

 

Thiopurines and Cyclosporine

Thiopurines, including azathioprine and 6-mercaptopurine, may improve inflammation in patients with UC. They inhibit the proliferation of lymphocytes and are used to maintain remission. Their dosing is weight-based and their onset of action can be slow, taking up to three months.²² They are often used in combination with biologics. Monitoring for drug interactions is necessary. Allopurinol interactions with thiopurines are especially important because allopurinol inhibits thiopurine metabolism.⁴⁶ The dose of mercaptopurine or azathioprine may need to be reduced to one-third or one-quarter of the normal dose if allopurinol is also prescribed. Prescribers determine dose reductions based on therapeutic response and toxicity.⁴⁷

 

Even though thiopurines and cyclosporine have been prescribed for many years, remaining aware of their side effects is important. Possible adverse events of thiopurines include nausea, vomiting, fever, leukopenia, thrombocytopenia, pancreatitis, and hepatotoxicity. Rare adverse events may include non-Hodgkin lymphoma. Individuals prescribed calcineurin inhibitors, such as cyclosporine, may experience hypertension, nephrotoxicity, hyperkalemia, infection, lymphoma, or diabetes mellitus.³⁷

 

Additional therapies include biologics and newer small molecules (tofacitinib, ozanimod). Before discussing newer therapies, a short review of step-up and step-down approaches is reasonable. If a patient presents with moderate to severe ulcerative colitis, philosophies differ among gastroenterologists regarding beginning with a step-up versus a step-down approach.^36,48

• The step-up approach begins with the traditional therapies mentioned above and followed by biologics and IMM if symptoms persist, if remission is not achieved, and the patient is considered high-risk. Extensive inflammation and the need for repetitive use of corticosteroids are examples of high-risk status.
• The step-down approach occurs when prescribers begin with a more intensive treatment with biologics and IMM and then step down to the medications mentioned above if patients improve.

 

Step Up or Step Down?

A 2021 study (N = 1891) examined UC’s clinical presentation in the five years before starting biologic therapy. The researchers analyzed patients’ experiences, comorbidities, morbidity, and treatment burden over time. Figure 2 summarizes participants’ health burden, disease progression, medication burden, and increased comorbidities. Across the study period, the need for treatment with oral corticosteroids, 5-ASA, and other non-biologic immunomodulators (IMM) increased progressively. Due to the increasing burden, the researchers supported early use of biologics (a step-down approach) rather than gradual step-up after failing conventional therapies for adult patients with moderate to severe UC.³⁰ 

 

Figure 2. Treatment and Health Experience Beginning Five Years Before First Biologic³⁰

5-ASA = 5-aminosalicylates; ED = emergency department; OC = oral corticosteroids; Pts = patients

 

 

Anti-TNF agents

 

Anti-TNF agents are commonly prescribed for moderate to severe UC due to their effectiveness, length of time on the market, and healthcare professional comfort prescribing them.⁴⁴ The U.S. Food and Drug Administration (FDA) has approved many anti-TNFs, but has approved only adalimumab, golimumab, or inFLIXimab for treating UC. Usually, prescribers use anti-TNFs after 5-ASA and corticosteroids in patients with mild to moderate severity and the step-up approach to treatment. Prescribers may prescribe the step-down approach, using biologics earlier, in some cases.³⁸ They often employ concomitant IMM to decrease immunogenicity seen with anti-TNFs.^38,47

 

Because biologics like anti-TNFs are made with living cells, patients may develop an unintended immune response (immunogenicity) in the form of anti-drug antibodies; if they develop, these antibodies may render the anti-TNF medication less effective. The antibodies may bind to the anti-TNF, interfere with its mechanism of action, reduce the anti-TNF’s serum concentration, increase its clearance, and lead to loss of effectiveness. Antibodies may also occur upon restarting an anti-TNF if a patient starts and stops an anti-TNF over time. It is unknown why some people develop anti-drug antibodies and others do not. The presence of antibodies and reduced response often prompt prescribers to switch the anti-TNF to regain effectiveness, and doing so often works. The addition of an IMM can suppress the antibodies which may reduce the risk of switching therapies or avoiding an anti-TNF dose increase.⁴⁷

 

Pharmacy team members should remain diligent about look-alike, and sound-alike names of the anti-TNF agents and should remember that doses of anti-TNF agents vary by indication.

 

SIDEBAR: TECH TALK about Look-alike, Sound-alike medications

Medications with names that look-alike and/or sound alike are classified as high-alert medications.

• Know that inFLIXimab had been confused with riTUXximab, so the Institute for Safe Medication Practices recommends using TALL Man lettering.
• Prevent medication errors between therapies for UC, such as adalimumab and golimumab, ustekinumab and upadacitinib, or vedolizumab and ustekinumab or adalimumab. Segregate the medications in different locations or consider stickers or other alert methods prior to medication dispensing.

 

 

An Anti-integrin

Integrins are adhesion receptors that mediate cell-to-cell and cell-to-extracellular adhesion. Vedolizumab is a humanized monoclonal antibody that binds to the α4β7 integrin, blocks the interaction of α4β7 integrin, and inhibits lymphocyte migration into inflamed GI tissue.⁴⁹ With fewer lymphocytes in the GI tract, vedolizumab helps reduce inflammation and UC symptoms. Vedolizumab can be referred to as a B-anti-integrin and an adhesion molecule inhibitor. Patients with steroid-dependent disease have treatment options, including treatment with thiopurines, anti-TNF agents (may be combined with azathioprine or 6-mercaptopurine), or vedolizumab.³⁸

 

Prescribers and patients may ask about outcomes in clinical trials. A vedolizumab study enrolled patients with an inadequate response or intolerance to IMM therapy (i.e., azathioprine or 6-mercaptopurine) and/or an inadequate response, loss of response, or intolerance to an anti-TNF.⁴⁹ Participants received IV vedolizumab 300 mg or placebo at week 0 and week 2. Concomitant stable dosages of 5-ASA, corticosteroids (prednisone dose of 30 mg/day or less or equivalent), and IMM (azathioprine or 6-mercaptopurine) were permitted through week 6. The percentage of patients achieving a clinical response at week 6 was 47%. The researchers also measured remission and found 17% of participants achieved remission at week 6. Those with a clinical response at week 6, or receiving open-label vedolizumab, were invited to enter a 52-week study with every 8-week dosing. At week 52, 42% of participants achieved clinical remission.⁴⁹

 

JAK inhibitors

 

Tofacitinib and upadacitinib are referred to as small molecules because their molecular structure is smaller and simpler than the biologics’, which are large three-dimensional structures. The JAK inhibitors are dosed orally and require a loading dose. JAK inhibitors are indicated for adults with moderately to severely active UC who responded inadequately or couldn’t tolerate one or more anti-TNF agents.³⁹ Many individuals are willing to visit an infusion suite for treatment; however, younger patients and those with very busy lifestyles or heavy travel schedules may prefer the small molecule oral drugs for their convenience.

 

When prescribing JAK inhibitors, pretreatment screening should include assessment for hepatitis B and tuberculosis. When patients start biologics or JAK inhibitors, their immune response may decrease, increasing risk of certain infections, such as hepatitis B or tuberculosis. If patients have active hepatitis B or tuberculosis, they need treatment to eradicate those infections before beginning biologics or JAK inhibitors. A risk of bacterial, viral, and herpes zoster infections exists, so prescribers must assess vaccination status before treatment. CBC and lipid panel monitoring is recommended. Prescribing tofacitinib in combination with biologics for UC or with potent IMM, such as azathioprine and cyclosporine, is not recommended.⁴⁰

 

 

IL-12/23 antagonist

Interleukin 12 (IL-12) and IL-23 are proteins that can cause inflammation. Ustekinumab is a human monoclonal antibody against the shared p40 subunit of IL-12 and IL-23 cytokines. Ustekinumab disrupts inflammation by blocking IL-12/23.⁴¹ The FDA has approved this biologic for adults with various forms of psoriasis, CD, and UC. (It is also approved for children 6 and older for various forms of psoriasis.) In UC in adults, it is typically administered as an IV induction dose, followed by subcutaneous maintenance dosing every eight or 12 weeks. Clinicians should screen for hepatitis B and tuberculosis and monitor CBC every six months.⁴¹ To minimize the risk of medication errors, pharmacy staff should double-check the prescribed route (IV or subcutaneous). They should also be alert for look-alike, sound-alike issues, to prevent prescription transcribing errors or other confusion between ustekinumab and the JAK inhibitor upadacitinib.

 

Research has documented outcomes for this monoclonal antibody, too. A ustekinumab clinical trial assessed efficacy and safety in adults with UC; the primary endpoint was clinical remission at week 8.⁴¹ The researchers randomized participants to a single IV dose of ustekinumab of approximately 6 mg/kg, 130 mg (a lower dose than recommended), or placebo at week 0. Enrollment required previous inadequate response to corticosteroids, IMM, or at least one biologic. At week 8, 19% of participants successfully reached clinical remission.⁴¹

 

S1P Modulator

Ozanimod is an oral sphingosine 1-phosphate receptor (S1P) modulator indicated for the treatment of moderately to severely active UC in adults.⁴² It is also approved for relapsing forms of multiple sclerosis, and the pharmacy team may field questions about this medication’s various indications. Ozanimod binds with high affinity to S1P receptors 1 and 5. It blocks lymphocyte trafficking from lymph nodes, reducing the number of lymphocytes in peripheral blood. Ozanimod may transiently decrease heart rate and cause atrioventricular conduction delays, so a low-dose starter titration pack is available. Prescribers should escalate the dosing slowly to avoid rare but significant bradycardia. Progressive multifocal leukoencephalopathy, a disabling, sometimes deadly adverse event, is rare but possible. Pharmacy teams should counsel patients regarding the need for effective contraception to prevent pregnancy; patients should use contraceptives for three months after discontinuing ozanimod.⁴²

 

An ozanimod clinical trial assessed efficacy and safety using a primary study endpoint of clinical remission at week 10.⁴² It enrolled adults with moderately to severely active UC if they had an inadequate response, or were intolerant, to specific other treatments. The treatments included oral 5-ASA, corticosteroids, IMM (e.g., 6-mercaptopurine and azathioprine), or a biologic (e.g., anti-TNF and/or vedolizumab). The proportion of patients reaching clinical remission at week 10 was 18% with an ozanimod dose of  0.92 mg once daily. Those achieving a clinical response were invited to be re-randomized to a 52-week study extension. The primary endpoint was the proportion of patients in clinical remission at week 52. The proportion of patients with an ozanimod dose of 0.92 mg once daily with clinical remission at week 52 was 37%.⁴²

 

MEDICATIONS IN DEVELOPMENT

Etrasimod is a once-daily, oral S1P receptor modulator in development for the treatment of UC. Results from the phase 2 OASIS trial and open-label extension study revealed patients with moderately to severely active UC who received etrasimod showed improvements in clinical remission and symptom relief beginning as early as week 2. In the phase 3 ELEVATE UC 52 study, 27% of patients in the etrasimod group achieved clinical remission compared with 7% of patients in the placebo group at 12 weeks.⁵⁰ Use of etrasimod in UC is not FDA-approved and regulatory authorities have not yet evaluated its safety and efficacy.

 

Risankizumab-rzaa is an IL-23 inhibitor that is FDA-approved for psoriasis and Crohn’s disease. It is in development for treatment of individuals with UC. In the INSPIRE trial, 20.3% of participants with intolerance or inadequate response to conventional or advanced therapies (biologics, JAK inhibitors, and S1P receptor modulators) achieved clinical remission at week 12.⁵¹ The FDA has not approved risankizumab in UC or evaluated its safety and efficacy.

 

Considerations for Medications in Therapy

Decision-making regarding UC treatment requires consideration of many factors, including

• disease and inflammation location, severity, and extent
• comparative effectiveness and long-term safety of available treatments
• treatment availability
• product labeling
• guideline recommendation
• prior treatment successes or failures
• cost, and
• patient preferences

Since some prescribers may dose escalate to an off-label (higher) dose or off-label shorter dosing interval, pharmacy teams need to remain alert regarding insurance policies that may impact treatment decisions.

 

Safety Information

Each medication’s full prescribing information includes comprehensive safety and efficacy details. The information in this section is not all-inclusive. It’s critical to keep in mind that all UC treatments have limitations. Because most infusions have similar adverse events, Table 5 summarizes select safety information and limitations regarding newer agents used in UC.

 

 

Table 5. Newer Agents: Select Safety Information and Limitations ^{37,41,42,49,52}

Limitations and Safety Considerations	Anti-TNF agents	Anti-IL-12/23 Agents	JAK Inhibitors	Anti-integrin	S1PR modulator
Immuno-suppression	√	√	√	√	√
Infection	√	√	√ (herpes zoster)	√ (upper respiratory)	√
Venous thrombo-embolism			√
Psoriasis	√	√
Major CV adverse event	√		√
Infusion/ injection site reaction	√	√	√	√
Malignancy	√	√	√	√	√
Tuberculosis	√	√	√	√
Worsen CHF	√
Lymphoma	√ (if combine with thiopurines)		√	√
Lymphocyte abnormalities			√
Anemia	√		√
Elevated lipids			√
Headache	√	√	√	√	√
Nausea	√		√	√	√
Fatigue	√	√	√	√	√
Liver function test elevations			√	√	√
Contra-indication if post-MI within 6 months, or unstable angina, stroke or TIA					√
Contraindicated if severe untreated sleep apnea					√
PML				√	√

MI = myocardial infarction; PML = progressive multifocal leukoencephalopathy; TIA = transient ischemic attack

 

Identifying drug interactions is a key skill for pharmacists. Of note, JAK inhibitors can interact with CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) and CYP2C19 inhibitors (e.g., fluconazole, omeprazole).⁴⁰ Drug interactions may be a concern with the use of ozanimod and concurrent IMM, tyramine, antiarrhythmics, beta blockers, or calcium channel blockers.⁴²

 

ACG and AGA Guidelines for the Management of Moderate-to-Severe UC

The American College of Gastroenterology (ACG) and the American Gastroenterological Association (AGA) published comprehensive treatment guidelines and interventions for UC.^31,44 Both guidelines cover achieving a response, induction of remission, and maintenance of remission. Select highlights presented below are not all-inclusive.

 

For remission induction, ACG recommends the following options³¹:

• In moderately active UC, oral budesonide MMX
• In moderately to severely active UC, oral corticosteroids
• In moderately to severely active UC, anti-TNF therapy
• When inFLIXimab is used as induction therapy for patients with moderately to severely active UC, it should include a thiopurine
• In moderately to severely active UC, or if failed anti-TNF, vedolizumab
• In moderately to severely active UC, tofacitinib 10 mg orally twice a day for 8 weeks
• For induction of remission in moderately to severely active UC with previous failure of anti-TNF therapy, tofacitinib

 

For maintenance of remission, ACG recommends the following options³¹:

• For previously moderately to severely active UC in remission due to corticosteroid induction, thiopurines
• Continue anti-TNF therapy after anti-TNF induction in patients with previously moderately to severely active UC
• Continue vedolizumab in previously moderately to severely active UC now in remission after vedolizumab induction
• Continue tofacitinib in previously moderately to severely active UC now in remission after induction with tofacitinib

 

The AGA provides the following recommendations for response and remission⁴⁴:

• Current evidence supports use of inFLIXimab, adalimumab, golimumab, vedolizumab, and tofacitinib for remission induction and maintenance in moderate-severe UC
• Thiopurine monotherapy should not be used for induction of remission but may be considered for remission maintenance
• Meta-analysis suggests that inFLIXimab and vedolizumab may be preferred first-line therapy in biologic-naïve patients, rather than standard-dose adalimumab or golimumab
• In patients with prior inFLIXimab exposure, particularly those with primary non-response to induction therapy, vedolizumab or tofacitinib may be preferred over adalimumab or golimumab
• Combination of a biologic agent with an immunomodulator is more effective than monotherapy with either agent
• In patients with moderate-severe disease activity, at high risk of colectomy, biologic agents with or without an IMM, or tofacitinib, should be used early rather than gradual step-up therapy after failure of 5-ASA
• Patients in remission with biologic agents and/or IMM, or tofacitinib, after prior failure of 5-ASA, may discontinue 5-ASA

 

PAUSE AND PONDER: What patient support questions may uncover a patient’s adherence challenges?

 

Patient Education Pearls for Patient Counseling

 

Pharmacy teams have numerous opportunities to provide UC patient education. Because the condition appears differently in affected individuals, conversations should align with the individual patient’s situation. Supportive patient education pearls addressing inflammation and advancing opportunities to remission should be individualized from these topics⁵³:

• UC’s exact cause is unknown
• UC affects people differs widely
• UC is a chronic condition and symptoms wax and wane
• Medications are available to control UC
• The number of people with UC has been increasing
• It can occur at any age and in any racial or ethnic group
• Symptoms will occur in the intestine and may occur outside of the intestine
• Ulcers in the intestine lining that bleed may lead to low red blood cell count (anemia)
• Ask the doctor what tests are needed
• Diet and nutrition plans differ for each patient
• Managing stress is important
• Have supportive friends and family
• Locate restrooms when outside the home
• Carry extra underclothes, toilet paper or moist wipes
• Ask for school or work accommodations

 

SIDEBAR: OTC and Alternative Therapies for Patient Discussion^34,35,44,54

 

Patients with UC may use these OTC products:

• Patients with UC may eat less, thinking it will decrease diarrhea. However, they need proteins, water, vitamins, and minerals to promote healing. Patients need vitamin D and calcium for bones if reduce their dairy intake.
• Bismuth subsalicylate (Pepto Bismol) is an antidiarrheal liquid, chewable tablet, and also swallowable tablet. It helps reduce inflammation in the intestinal lining. Remind patients that it darkens stool and the tongue. That darkening is not a medical concern.
• Simethicone (Gas-X) is an anti-flatulent that helps form gas bubbles in the digestive tract, making them easier to pass and relieving gas pain.
• Loperamide (Imodium) should be taken with caution. It slows digestion. Occasional use may be effective, but patients should consult healthcare providers if they contemplate ongoing use.
• If mild disease persists, such as seen with a Mayo score of 1, the AGA guidelines and some advocacy web sites mention curcumin (a phytochemical from turmeric) or suggest adding curcumin and probiotics for some individuals suffering with UC.
• Patients with severe disease, frequent bleeding, anemia, or abnormal laboratory results may need folic acid. The usual folic acid dose is 1 mg/day. Asparagus, broccoli, and spinach are also foods that contain folate or folic acid.

Patients who have UC should avoid these OTC products:

• Patients should consult their healthcare providers whether to avoid aspirin, nonsteroidal anti-flammatories (ibuprofen, naproxen), lactose, sugar substitutes, or preservatives.
• Patients who take sulfasalazine or mesalamine should not take them with antacids.

 

Many institutions, hospitals and healthcare providers have created UC resources. Table 6 lists  examples of supportive options that can be shared with individuals with UC.

 

Table 6. Patient and Clinician Resources to Support Individuals with UC

Resource	Contact
American College of Gastroenterology	https://gi.org/topics/ulcerative-colitis/ ·       Describes symptoms, tests, diagnosis, risks, surgery and treatments
Cleveland Clinic: Butts and Guts podcast	https://my.clevelandclinic.org/podcasts/butts-and-guts ·       Covers a wide range of gastrointestinal issues including management and surgery ·       Use the search term “ulcerative colitis”
Crohn’s and Colitis Foundation (CCF)	Help Center (referrals, insurance info) https://www.crohnscolitisfoundation.org/ info@crohnscolitisfoundation.org 1-888-MY-GUT-PAIN (888-694-8872- extension 8) Signs and Symptoms https://www.crohnscolitisfoundation.org/sites/default/files/legacy/assets/pdfs/living-with-ulcerative.pdf Spanish Help Center https://www.crohnscolitisfoundation.org/es/home School Accommodation Suggestions https://www.crohnscolitisfoundation.org/justlikeme/living-with-crohns-and-colitis/school/school-accommodations
Mayo Clinic	https://www.mayoclinic.org/diseases-conditions/ulcerative-colitis/symptoms-causes/syc-20353326 ·       Includes a video and written materials on diagnosis, symptom management, and treatment
Downloadable Mobile Apps ·       Download from the App Store or Google Play	My IBD Care: tracks symptoms, flares, medical appointments, BMs, medications Bathroom Scout: Identifies 1.3 million public toilets MyPlate: Monitors calories, the nutrition content of food MyColitis: Health tracking of bowel movements, medications, moods, symptoms, tests

 

CONCLUSION

UC is a debilitating chronic IBD that usually requires long-term treatment to control symptoms and prevent disease-related complications. Many treatments are available; however, the effectiveness, safety, and durability of response and remission vary, and careful assessment of these factors must drive a personalized approach to care. Pharmacy teams must recognize that every patient’s disease is different, and results in diverse manifestations. Pharmacists and pharmacy technicians are ideally positioned to collaborate with multidisciplinary teams to support strategies tailored to each patient to optimize care and to help patients maintain a positive outlook.

 

Many unanswered questions remain about UC. Researchers will continue to evaluate treatment advances and explore disease management opportunities while pharmacy teams encourage patients suffering from UC to have routine doctor visits, adhere to their medication regimen, and maintain a healthy lifestyle.

 

 

 

 

Download CE Activity

 

Introduction and Epidemiology

The American Pet Products Association (APPA) estimates that approximately 70% of Americans keep pets in their household, equating to 90.5 million homes. Dogs and cats are the most popular and live in around 69.0 and 45.3 million U.S. households, respectively, followed by 11.8 million households for freshwater fish, 9.9 million households for birds, and 3.5 million households for horses.¹ Public, residential, leisure, and specific occupational environments (e.g., farms, laboratories, pet shops) have high concentrations of pet allergens because of the high prevalence of community pet-keeping and Americans’ tendency to live indoors. Allergic reactions to pets have been recognized for at least 100 years.² Risk factors for developing asthma and rhinitis include allergies to furry animals, especially cats and dogs.³ Direct or second-hand pet exposure increases the likelihood of exacerbating disease in pet-sensitive people. However, evidence also shows that early childhood exposure to dogs or cats before one year of age may have protective effects in preventing allergic sensitization.⁴

Notably, allergies to unusual or exotic pets have increased over the last decade.⁵ In many urban areas, apartment complexes prevent owning large pets or charge a fee for owning cats and dogs, leading to the choice of smaller, more unusual animals. Some examples of uncommon pets are rodents (mice, rats [which allegedly make very good pets], guinea pigs, and other mammals like ferrets, pigs), amphibians (axolotl [a Mexican salamander], dart frogs, and fire belly newts), and reptiles (snakes).⁶ The allergic signs and symptoms or diseases associated with uncommon pets are like those manifested in cat and dog allergies. In addition, patients may present with respiratory symptoms induced by bird allergens and gastrointestinal symptoms after consuming bird eggs; this is called a bird-egg syndrome.⁷

Overall, the incidence of specific allergy to exotic or uncommon pets is unknown because literature only includes isolated cases or small series. In the United States, an estimated 15% to 30% of people are allergic to their pets.⁸ Among people with pet allergies, a fraction is sensitized to more than one animal. Moreover, according to the Asthma and Allergy Foundation of America, cat allergies are reported twice as often as dog allergies. Animals are also recognized as the third leading cause of allergic asthma, after mites and pollens.⁸ Many people adopt ferrets or rabbits, believing they are hypoallergenic. They are not, and pharmacy staff should be aware of that fact.^9,10 The most frequent allergic reactions result from inhalation, contact, or bites.

This continuing education activity summarizes knowledge of pet allergens, including those from uncommon pets; the allergy reaction mechanism and its signs and symptoms; current advances in diagnosis and treatment methods such as immunotherapy; and recommendations for patient education and counseling.

Pause and Ponder: When patients ask about medication for pet allergies, what kinds of questions should you ask?

PET ALLERGENS

Allergy Mechanisms

Compared with other conditions’ mechanisms, allergy mechanisms are simple and encompass three specific paths: allergic sensitization, allergy, and cross-reactivity.¹¹

• Allergic sensitization is the presence of immunoglobulin E (IgE) antibodies to an allergen.
• Allergy is the occurrence of reproducible symptoms or signs initiated by exposure to a defined stimulus at a dose tolerated by nonallergic persons and mediated by specific immunologic mechanisms. If no symptoms develop, a person could be sensitizing to a particular allergen but not be allergic.
• Cross-reactivity is the process of IgE antibodies (originally developed against a given allergen) binding to homologous molecules originating from a different allergen source.

Characterizing Pet Allergens

Allergies to pets are common. Pet allergy is an allergic reaction to proteins (allergens) found in animals’ skin cells (dander), saliva, urine, or sweat on their fur.⁵ Allergens within the same protein family can cause cross-reactivity. Most allergens are spread via airborne particles. Dander contains allergens formed in sebaceous gland secretions and saliva. Secretions containing allergens adhere to the hair and stratum corneum of the skin. When an animal sheds, tiny particles disperse into the air and remain buoyant for an extended period of time. After the particles slowly settle onto the floor, furniture, or other items, they can be easily re-dispersed into the air. As a result, pet-sensitive people could experience allergy symptoms in the nose, eyes, and respiratory tract even if the pet is not present.⁵ Additionally, people can carry pet allergens that settled onto their clothing or hair.

For cats and dogs, the primary allergen sources are dander and saliva. Similarly, the primary allergen source in rabbits is saliva. In contrast, the primary allergen source is urine in rodents (e.g., mouse, rat,) and Mustelidae (ferrets and minks).

Rodents are an interesting case study. Most research laboratories experience a very high rate of staff turnover because lab workers develop allergies to rodents. Children who are exposed to rodent urine can develop this allergy, too. Male rodents produce a larger quantity of and more condensed urine than female rodents. This explains why people who commonly come in contact with male rodents are more likely to develop allergic symptoms. Allergy to rodents acts as an occupational hazard for researchers. Mouse urine is the most concentrated of all urines—far more concentrated than any other species.¹² One study showed that 30% of people exposed to mice and 13.7% of people exposed to rats suffered from allergy symptoms.¹² Symptoms range from conjunctivitis to asthma to skin reactions, which makes working with these animals difficult.

Most animal allergens belong to one of three primary protein families. Within the three families, lipocalin-like proteins and the serum albumin family are the two most widely studied. Other identified allergens are considered minor, including gelatins, immunoglobulins, and transferrins presented in secretions and dandruff. Knowledge of these allergens’ allergenicity and cross-activity is essential to improve treatment and prevent allergic reactions. Table 1 summarizes partially characterized pet allergens, including those generated by exotic pets, because not all allergens are fully characterized.⁵

 

Table 1. Summary of Characterized Pet Allergens^13-22

Common Name of Animal	Source	Allergen	Family
Dog	Dander, saliva, hair	Can f 1 (major allergen) Can f 2 Can f 4 Can f 6 Can f 3 Can f 5 Can f 7 Can f 8	Lipocalin Lipocalin Lipocalin Lipocalin Albumin Arginine esterase (kallikrein) Epididymal secretory protein E1 or Niemann Pick type C2 protein Cystatin
Cat	Sebaceous, anal, and salivary gland	Fel d 1 (major allergen) Fel d 2 Fel d 4 Fel d 7 Fel d 3 Fel d 5w Fel d 8 Fed d 6w	Uteroglobin Albumin Lipocalin Von Ebner gland protein Cystatin Cat IgA Latherin-like IgM
Horse	Dander, sublingual, submaxillary salivary glands, and urine	Equ c 1 (major allergen) Equ c 2 Equ c 4 Equ c 3 Equ c 6	Lipocalin Lipocalin Latherin Albumin Lysozyme
Chinchilla	Epithelia, saliva, urine	Chi La Chi Lb	Protein kinase inhibitor Lipocalin
Guinea pig		Cav p 1 (major allergen) Cap p 2 (major allergen) Cap p 3 Cap p 4 Cap p 6	Lipocalin Lipocalin Lipocalin Serum albumin Lipocalin
Gerbil	Epithelial, salvia, urine, sleep bed	Mer un 23kDa Mer un 4	Lipocalin Serum albumin
Siberian hamster	Epithelial, saliva, urine	Phod s 1	Lipocalin
Rat		Rat n 1 (major allergen) Rat n 4 Rat n 7	Lipocalin; alpha-2u-glubulin Serum albumin Immunoglobulin
Mouse		Mus m 1 (major allergen) Mus m 2 Mus m 4 Mus m 7	Lipocalin; urinary prealbumin Unknown Serum albumin Immunoglobulin
Rabbit		Ory c 1 Ory c 2 Ory c 3 Ory c 4	Lipocalin Lipocalin Secretoglobin Lipocalin
Ferret		Mus p 17 Mus p 66	Unknown Serum albumin
Pig	Meat	Sus s 1 Sus s 5 Sus s 6	Serum albumin Lipocalin Serum albumin

Lipocalin Superfamily

More than 50% of allergens identified from furry animals belong to the lipocalin superfamily and are found in animal dander, saliva, and urine.²³ Lipocalins are large proteins and can induce IgE production in a large proportion of atopic individuals (people who have enhanced immune response to common allergens) who are exposed to the allergen source.²⁴

Serum Albumin Family

Serum albumin is a globular protein prone to participation in IgE-mediated cross-reactions.²⁴ Serum albumin is commonly found in pet dander and saliva and causes an allergic reaction by inhalation and ingestion.

Secretoglobin Superfamily

Secretoglobins are the most potent allergens in cats (e.g., Fel d 1) and other pets (e.g., rabbit Ory c 3). Produced by the skin, salivary and lacrimal glands, these proteins have an unknown function. Dried saliva and dandruff are spread as airborne particles and cause sensitization in susceptible people.²⁵

SIGNS AND SYMPTOMS OF PET ALLERGIES

The most frequently observed pet allergies result from inhalation, contact, and bites. The main allergic symptoms are similar across both common and uncommon pet types. They present as rhinitis, conjunctivitis, urticaria (red, itchy welts that result from a skin reaction), and lower and upper respiratory symptoms, which can be mild to severe and rarely cause anaphylactic shock.⁵

Hypoallergenic Pets

“Hypoallergenic” is defined as possessing decreased risk of causing an allergy in people, which means that hypoallergenic animals could still elicit allergies in humans.⁹ To make hypoallergenic animals, breeders or researchers combine breeds that produce less allergen (in dogs, breeders use breeds that shed less than other breeds, or have hair rather than fur). However, animals often have different mechanisms of allergenicity, so infrequent shedding does not solve all allergy problems.

In a dog allergen study, homes that included hypoallergenic dogs had no statistically significant difference in dog allergen levels compared to homes that included non-hypoallergenic dogs. The common allergen in dogs, Can f 1, was reported at similar levels in all groups.²⁵ The frequency of shedding varies in different dog breeds, but all dogs can elicit allergies in humans.

The main allergen in cats, Fel d 1 protein, comes from their saliva and sweat glands. Because of its small size and adhesiveness, Fel d 1 floats around and sticks to everything, making it almost impossible to remove physically. In fact, Fel d 1 measures in at less than one-tenth the size of ribosome; it’s so small, it easily navigates its way deep into the lungs and can precipitate asthma.²⁶ For this reason, making a completely hypoallergenic cat has proven impossible, however vaccines to decrease the production of Fel d 1 protein have been studied; one vaccine is a combination of recombinant Fel d 1, tetanus toxoid protein, and a snippet of the coat of a plant virus.²⁷ Researchers are unsure as to the purpose of Fel d 1 in cats or why levels of Fel d 1 vary.

Ferrets—which are related to otters, minks, weasels—are considered hypoallergenic because they are less likely to cause an allergic reaction compared to other animals. However, they can still provoke allergies in people. Allergies to ferrets come from their hair, saliva, and urine. Ferret hair and saliva is usually easy to control because they shed infrequently and do not lick people like dogs and cats often do. However, urine is harder to control and can cause allergies when owners clean crates.⁹

Rabbits produce allergens through dander, hair from shedding, and saliva. They tend to shed more often than ferrets, around every three months, so keeping up with cleaning may be difficult. Rabbit hair isn’t naturally allergenic, but when rabbits lick their fur, they transfer a saliva protein that is contaminated with the protein allergen.¹⁰

DIAGNOSIS

Skin Prick Test

Allergists (allergy specialists) use skin prick tests together with medical history and physical examinations to rule out or confirm a suspected IgE-mediated animal allergy.²⁸ Manufacturers prepare skin prick tests by extracting natural allergens from animal hair, dander, and urine. The doctor or nurse will prick the patient’s skin on the forearm or upper back and determine if an allergic reaction occurs within 15 minutes. If a patient develops a red, itchy bump where the pet allergen extract is pricked into the skin, the patient is allergic to that pet allergen. Diagnosticians should first use a skin prick test as it is inexpensive, easy to use, and quick to perform. However, allergen concentrations and components are inconsistent, varying among similar commercial tests from different manufacturers. Healthcare providers should be aware that patients’ test results may be inconsistent if they use different skin prick tests at different times.²⁸

Serum-specific IgE Test

Allergists can use a serum-specific IgE (blood) test when patients’ symptoms and skin test results are contradictory or when patients’ skin conditions prevent a skin test. Serum-specific IgE tests can only determine if a patient is sensitized to a specific pet allergen, but it cannot determine if a patient is allergic to that allergen. Serum-specific IgE tests are highly sensitive, but prone to false-positive results. From this perspective, serum-specific IgE tests may be less accurate than skin prick tests.²⁹

Molecular Diagnosis

Recent scientific advances have allowed molecular diagnosis to differentiate patients who are allergic to a single species or sensitized due to cross-reactivity. This method can aid targeted recommendations for avoidance and assess the choice and composition of immunotherapy.²⁸

PET ALLERGY MANAGEMENT

Pet allergies cannot currently be cured. The treatment goal is to control symptoms and improve patients’ functional status and well-being.

Nonpharmacologic Treatment – Avoid & Minimize Allergen Exposure

Current recommendations for managing pet allergy symptoms start with exposure avoidance. Starting when animals are young, bathing them at least once weekly can reduce allergens and eliminate reactions in humans who are exposed to them (see SIDEBAR).³⁰ Immediate removal of animals from the household will not alleviate symptoms if the owner has carpeting and other pieces of furniture/items that the pet slept or sat on. Mammalian allergens are stable and can persist in house dust for up to six months.³² Additionally, using high-efficiency particulate air (HEPA) filters and mattress encasement, vacuuming, and chemically treating carpet are alternative methods for reducing exposure to contaminated materials, but may not reduce disease severity.³³

Pause and Ponder: When patients have pet allergies, which symptoms are best treated with antihistamines?

SIDEBAR: To Bathe or Not to Bathe…^26,31

Bathing a cat or dog regularly appears to reduce the quantity of allergen harbored by the pet. To effectively lower Can f 1 concentrations, owners need to bathe the animal at least twice every week because Can f 1 concentrations rise rapidly, approaching baseline concentrations within three days after washing. Twice-weekly bathing can reduce the amount of recoverable Can f 1 on dogs by more than 80%, but researchers note that ideally, one would bathe the dog two to three times every week. Airborne Can f levels can fall by ruff-ly 40% but will quickly escalate.

However, the beneficial effects of reducing allergen levels by regular bathing are more likely associated with dogs, because their allergen burden returns faster than that of cats. So, bathing animals reduces the amount of allergen far better than vacuuming.

But should companion animals be bathed so often?

Most cats are notoriously averse to bathing, although some breeds like water (i.e., the Bengal). Dogs vary in the response to bathing—some like it, others do not. People who plan to bathe their cats or dogs regularly should do three things:

• Check with a veterinarian or a breed advocacy group. The American Kennel Club indicates that how often an owner should bathe a dog depends on the dog’s coat type and presence or absence of an undercoat (in the latter case, frequent bathing can affect a dog’s temperature regulation). Bathing an animal is not just about a human’s allergies, the animal’s health and welfare should be a primary concern.
• Consider the labor and time involved in bathing a pet often, safely, and well.
• Start when the animal is young.

 

An allergen reducing cat food (Pro Plan LiveClear) is now available, and its manufacturer indicates it reduces the number of allergens in cat hair and dander by 47% after three weeks of feeding.³⁴ It is produced using eggs that contain an anti-Fel d1 antibody. When cats consume the food, the egg powder binds to and neutralizes Fel d1 in the cat’s saliva.³⁴

Pharmacologic Treatment

When avoidance and reducing allergens are not enough, depending on the severity of signs, over the counter (OTC) medications like antihistamines or local/topical steroids may provide temporary relief of allergy symptoms.³⁵ Those symptoms include runny/itchy nose or throat, sneezing, and itchy, red or watery eyes. Combination products that contain both an antihistamine and a decongestant or an analgesic are available but should be used with caution due to the increased risk of adverse effects. Other allergy medications, besides the ones mentioned above, are used less often, including mast cell stabilizers and leukotriene antagonists. Table 2 summarizes common medications (both OTC and prescription) for treating mild to moderate allergy symptoms.³⁵

Table 2. Medications to Treat Allergy Symptoms³⁶

Medication	Mechanism of Action	Adverse Effects	Notes
Antihistamines
1st generation (nonselective, more sedating) * Diphenhydramine, chlorpheniramine, clemastine 2nd generation (less sedating, less drowsiness): Cetirizine,* desloratadine,* fexofenadine,* levocetirizine,* and loratadine* Azelastine has nasal spray* and eye drop formulation. Epinastine and olopatadine* are formulated as eye drops.	Blocks histamine and its binding to receptors, prevents histamine-caused redness, swelling, itching, and changes in secretions during an allergic response	·       Drowsiness ·       Fatigue ·       Headache	The 2nd generation antihistamines are preferred over 1st generation based on safety and efficacy data.
Corticosteroids
Available as tablets, liquids, nasal spray, topical creams for skin allergies, topical eye drops for conjunctivitis.   Some steroids include: beclomethasone, ciclesonide, fluticasone furoate,* mometasone, budesonide,* triamcinolone,* dexamethasone ophthalmic, prednisone, etc.	Anti-inflammatory effect	Short-term use: Weight gain, fluid retention, high blood pressure   Long-term use: Growth suppression, diabetes, cataracts of the eye, osteoporosis, muscle weakness   Side effects of inhaled steroids: Cough, hoarseness, fungal infection of the mouth	Highly effective for allergies but must be taken regularly. It may take 1 to 2 weeks before the full effect.
Decongestants
Available as nasal sprays, eye drops, liquids, and tablets   Some decongestants include: pseudoephedrine,* phenylephrine,* and oxymetazoline* nasal sprays	Shrinks swollen nasal tissues and blood vessels to relieve the symptoms of nasal swelling, congestion, mucus secretion, and redness	·       Increased blood pressure ·       Insomnia ·       Anxiety, feeling nervous, restlessness	Relieve congestion and are often prescribed with antihistamines for allergies   Contraindicated in patients with severe coronary artery disease, severe hypertension, and who concomitantly use monoamine oxidase inhibitors   Short-term use only (~5 days). Long-term use can make symptoms worse.
Combination Allergy Drugs
Some combination drugs include: cetirizine/pseudoephedrine,* fexofenadine/ pseudoephedrine,* diphenhydramine/ pseudoephedrine,* loratadine/pseudoephedrine,* pseudoephedrine/triprolidine* for nasal allergies, and naphazoline/pheniramine* for allergic conjunctivitis	Effects from each component	Side effects from each component	Use with caution due to increased risk of adverse effects
Anticholinergic Nasal Spray
Ipratropium bromide nasal spray to control nasal discharge	Antisecretory properties in the nasal mucosa	·       Bitterness of the mouth ·       Dry nose, nosebleeds, or irritation ·       Dizziness ·       Headache ·       Sore throat ·       Respiratory tract infection	Some patients may feel better right away. For others, it may take 1 to 2 weeks before the medicine helps. It is important for patients to continue use of this medication as instructed.
Mast Cell Stabilizers
Available as eye drops for allergic conjunctivitis and nasal sprays for nasal allergy symptoms   Some mast cell stabilizers include cromolyn sodium,* iodoxamide-tromethamine, nedocromil, pemirolast, etc.	Prevents histamine release from mast cells	Throat irritation, coughing, skin rashes   For eye drops may cause blurred vision, stinging, and burning	For mild to moderate symptoms Not as effective as steroids
Leukotriene Modifiers
Montelukast*: Indicated for adults and pediatric patients six months or older with perennial allergic rhinitis. May be less effective than loratadine or cetirizine for reducing daytime nasal symptoms	Montelukast binds to leukotriene receptors in the human airway (smooth muscle cells and macrophages), preventing airway edema, smooth muscle contraction, and other respiratory inflammation	·       Stomach pain or upset ·       Headache ·       Stuffy nose ·       Cough ·       Fever ·       Rash ·       Irritability	Warn patients to report behavior changes, including suicidal ideation or suicidal behavior Avoid concomitant use of aspirin or NSAIDs in aspirin-sensitive patients
*Indicates over the counter (OTC) medication

 

In general, for conditions eligible for self-care, e.g., allergic rhinitis, patients should start taking OTC allergy medications one week before they expect symptoms from a predictable exposure or as soon as possible before allergen exposure (for episodic exposure).³⁵ Prescribers should tailor the pharmacologic therapy and length of treatment based on symptoms and severity. Usually, complete relief takes two to four weeks. Intranasal steroids control nasal symptoms more effectively than antihistamines, as they inhibit multiple cell types and mediators, and should be recommended for moderate or persistent allergic rhinitis. Decongestants are effective in nasal congestion but have little effect on other symptoms. Intranasal and ocular preparations are available for nasal and eye symptoms. Intranasal cromolyn is the preferred initial choice for pregnant or lactating patients, as the body does not absorb it based on the route of administration. As mentioned in the table, fluticasone and triamcinolone nasal sprays are available over the counter.³⁵

If a patient has persistent allergies, allergy medication is more effective when taken regularly.³⁵ For example, if a patient with moderate or severe persistent allergic rhinitis has completed two to four weeks of treatment with intranasal corticosteroids or oral antihistamine and achieved symptomatic control, healthcare providers can optimize the treatment’s effect by reducing the dose and continuing treatment for one additional month. If a patient’s symptoms are uncontrolled after two to four weeks of OTC treatment, pharmacists should assess the patient’s adherence and refer for prescription therapy if necessary.³⁵

Pause and Ponder: Which providers in your area provide allergen-specific immunotherapy? What should patients expect if they take this route?

Allergy Immunotherapy

Allergen-specific immunotherapy has been used in pet allergies for years and has proven efficacy to help control symptoms and prevent disease progression. Allergists will consider allergy-specific immunotherapy when symptoms are uncontrolled by medications and/or avoidance measures, when adverse drug effects are intolerable, or when patients want to reduce long-term use of allergy medications.³⁷

The basis for allergen-specific immunotherapy is gradual reprogramming of the immune system to build a tolerance to allergens. This class comes in three forms:

• Sublingual allergy immunotherapy (SLIT) tablets
• SLIT drops, and
• subcutaneous allergy immunotherapy (SCIT)

As of 2022, the FDA has approved four SLIT tablets to treat allergic rhinitis with or without allergic conjunctivitis caused by ragweed, northern pasture grasses, and dust mites in susceptible individuals; the FDA has not approved SLIT tablets for pet allergies.²²

SLIT drops are made from FDA-approved allergy extracts used to make SCIT shots. However, these extracts are only FDA-approved for injection use under the skin, and they are not approved for use under the tongue. Therefore, SLIT drops are not FDA-approved and are off-label in the United States, and Medicare or Medicaid does not cover these treatments in most cases. Despite not having FDA approval, patients can still receive SLIT drops from some prescribers who prepare a custom-mixed formulation but must pay out of pocket. Research indicates SLIT is safe and effective.³⁹

The FDA has approved SCIT for cat allergies, but not for other pet allergies. Patients who receive SCIT usually call it “allergy shots.” One systemic review evaluated 88 trials that enrolled 3,459 asthmatic patients and exposed them to SCIT. One case of deterioration in asthma symptoms was avoided for every three patients treated with SCIT (95% CI, 3-5), and one patient would avoid increasing symptomatic medication use for every four patients treated (95% CI, 3-6).⁴⁰ Another study found that SCIT can reduce the need for systemic steroids in allergic rhinitis patients.⁴¹ Usually, the patient receives a solution for injection with 10,000 bioequivalent allergy units (BAUs) per milliliter (standardized extract) of lyophilized cat hair and dander added to glycerol and human serum albumin (0.03%). A clinician administers one to two subcutaneous injections every week starting at low doses (1:10,000 dilution) and titrating up to a seemingly effective maintenance dosing. Then, the prescriber extends the injection interval gradually to every 2 weeks to 4 weeks. For cat allergens, the effective maintenance dose usually falls within the 1000 to 4000 BAU range.⁴²

SCIT sometimes can cause treatment-related systemic allergic reactions; however, near-fatal or severe reactions are rare, and most reactions are local and mild (swelling, pruritis, and redness at injection site).⁴³ SCIT should not be recommended to patients who have severe uncontrolled heart problems or asthma if they take beta-blockers, which are associated with more frequent reactions, more severe reactions, and reactions that are refractory to epinephrine. Additionally, allergy shots should not be recommended for pregnant women unless discussed with their obstetricians.⁴³

Both SCIT and SLIT require gradual up-titration of dosages with ongoing and multiple treatments and may take three to five years to reach desensitization. Also, for SCIT, based on its route of administration (subcutaneous injections are invasive), patients will need to visit the doctor's office more frequently and may experience the treatment-associated side effects.

SLIT has been increasingly recommended because of its ability to modify the immune system for the long term while reducing allergy symptoms. SLIT also showed a safer profile, only associated with mild mouth symptoms, and improved adherence compared to SCIT.⁴⁴ When compared to traditional allergy treatments, SLIT tablets showed similar clinical efficacy to nasal corticosteroids and greater clinical efficacy than second-generation antihistamines and montelukast.⁴⁵

What About Cost?

In adherent patients, SCIT and SLIT have proven to be an economically viable option. The annual cost of using SCIT depends on patients’ insurance: Medicare ($1021.70), Medicaid ($758.16), and the commercial average ($1722.24). Yearly treatment costs for SLIT are self-pay because treatment is not FDA approved and costs around $679.25.⁴⁶ Because SLIT drops are administered at home by patients, they tend to be more affordable than the cost of SCIT. Patient preference might be for a once monthly administration, rather than taking oral antihistamines  daily.

OTC medications are less expensive than immunotherapy, but costs vary. In a comparison of second-generation antihistamines versus montelukast, levocetirizine (Xyzal) had the best efficacy per cost value. Generic fexofenadine (Allegra), although similar in efficacy, was more expensive than levocetirizine.⁴⁴

CONCLUSION

Healthcare providers should counsel patients about reducing allergen exposure and help patients to choose OTC medications for self-care based on individual patient needs and conditions to optimize treatment effects. Pharmacy staff should refer patients to allergists when necessary to identify the cause of their allergy symptoms. If a patient's allergy does not allow him or her to have pets at home and the patient owns a pet, suggest that the patient ask family members or friends about placement before contacting the local animal shelters.

Download CE Activity