Apoquel® The NVDS Experience: Where Are We Now?
Apoquel® (oclacitinib, Zoetis), has been a remarkable medication for the reduction of pruritus in dogs that we manage as veterinary dermatologists. We thought it would be helpful to share our clinical experiences.
Use of Apoquel® in the management of canine atopic dermatitis (CAD) has greatly reduced our need for adjunctive systemic glucocorticoids in managing CAD. It is rarely used as a sole therapy in our patient population. We prescribe Apoquel® for acute flares in chronic CAD, as chronic adjunctive therapy in CAD that is partially controlled with other treatment modalities and as seasonal therapy in CAD that is limited to a few months of the year.
In addition, we will use Apoquel® for reduction of itch in dogs with flea bite hypersensitivity while flea control is being instituted, for reduction of itch in dogs with sarcoptic mange while ectoparasite treatment is instituted, for control of itch with dogs suspected to have food sensitivities while a food trial is being started and for reduction of itch in dogs with pyotraumatic dermatitis along with other interventions.
Although Apoquel® is a remarkable tool, we cannot emphasize enough the importance of identifying and treating preexisting infections when one is considering using the drug. Secondary bacterial and yeast skin infections can occur while dogs are on Apoquel® and rechecks while on the drug are important to diagnose and treat these infections. We have had several German shepherd dogs develop widespread deep pyodermas and several short-coated dogs develop interdigital folliculitis and furunculosis as new problems whilst on Apoquel®. Apoquel® had to be discontinued during antimicrobial therapy in order to resolve these new infections.
Periodic reevaluation of dogs on Apoquel® is important so that one may identify new problems and lesion types that require attention. Although rare, demodectic mange has been observed in dogs while on Apoquel®. If alopecia, erythema, hyperpigmentation, comedones or any new lesion is noted, deep skin scrapings (as well as skin surface cytology) is indicated. In addition, Apoquel® does not appear to be helpful in the management of allergic or infectious otitis externa. Perform otoscopic examinations and ear cytologies as indicated. Treat any infection identified. Apoquel® does not appear to reduce epithelial hyperplasia occurring with chronic otitis.
Continue to encourage year-round flea control in dogs that have a chronic primary pruritic skin condition. Apoquel® may reduce the itch associated with flea bite hypersensitivity, but it is not a flea control product. Fleas may exacerbate or flare CAD. Similarly, if one suspects or confirms pruritus is attributable to sarcoptic mange, ensure that ectoparasite treatment is instituted whilst starting Apoquel®. We have seen several cases of sarcoptic mange in dogs while on Apoquel® because only pruritus was addressed.
Our pet clients have provided us excellent feedback. For some dogs, the duration of action of Apoquel® does not seem cover the 24 hour dosing interval. To address this, we recommend the use of antihistamines in the evenings and dose the Apoquel® in the mornings. About 20% of dogs in our practice experience a modest escalation in severity of itch when transitioning from the initial twice daily dosing to once daily dosing of Apoquel®. Over time, at the once daily dose, the severity of itch seems to decrease to acceptable level. When talking with owners about this, we continue to encourage them to work through the differential diagnoses to identify and control the primary disease causing pruritus. We are also noting that there seems to be a diminished response to Apoquel® over time. At this time, we do not have an immunologic explanation for this observation. However, knowing that this is potential, we continue to pursue the primary disease causing pruritus.
One of the greatest benefits in veterinary dermatology practice is that we now have an effective medication that can control itch while we are in the process of allergy testing pets. For the most part, serum and intradermal testing may be done while a pet is taking Apoquel®. From time to time, we may discontinue Apoquel® for testing. Previously, we would have to discontinue antipruritic therapies before intradermal testing and pets were uncomfortable during this time. In some cases, we would be unable to allergy test a dog due to the inability to withdraw from glucocorticoids.
Apoquel® Side Effects
FDA approval studies have evaluated the safety of Apoquel®. The product label reviews those results. We do not recommend off label usage of Apoquel®, and do not recommend use in cats at this time. Side effects to Apoquel® are few. The very rare dog will have diarrhea. Several observations have been made by other veterinary dermatologists using Apoquel®. None have been critically evaluated in the peer-reviewed literature to date. Studies are ongoing. There have been anecdotal reports of individual cases of demodicosis, viral papillomatosis, weight gain thought to be related to the decrease in calorie expenditure from previously pruritic behaviors, urinary tract infections (UTI), proteinuria that may be associated with occult UTI or other cause, notable leukopenias and ALP elevations. Dogs on Apoquel® have developed malignancies, but care should be taken in attributing their development to use of Apoquel® at the prescribed dosages; use of Apoquel® has not been found to be causal. As per the product label, we do not recommend use of Apoquel® in dogs with a previous history of malignant neoplasia of any type.
How Do We Monitor Pets on Apoquel®?
Routine scheduled reevaluations are recommended. Some dogs should have pretreatment lab work and urinalysis. We use our clinical judgment in making those recommendations. Typically, a CBC, blood chemistry and UA are done one to three months into treatment with the drug and then every six to 12 months thereafter while the dog remains on the Apoquel®.