management of our allergic dermatitis patients that suffer from
severe inflammation of the skin and often intense and unrelenting pruritus. Even better, since it is so specific in its targets, the
collateral damage side effects of corticosteroids and cyclosporine that are currently used to control allergies in dogs are essentially eliminated.
that said, as you know, veterinarians are a bold and inquisitive
group. There is a lot of scuttlebutt out there about other potential uses for a drug of this nature. I (and I am sure Zoetis) do
not advocate any non-label use of Apoquel but I will be curious to see what other uses veterinarians find for this drug.
What are the known side effects of Apoquel?
When should Apoquel be used?
Apoquel is labeled for use in dogs for the treatment of allergic
dermatitis. We should never assume that a drug of this nature is
totally benign so it makes sense to confirm the diagnosis of
allergies before starting use. One must always rule out other
causes of pruritus including external parasites, pyoderma,
malassezia infection, dermatophytosis and occasionally neoplasia and endocrinopathies. Only when the other conditions
have been ruled out can a diagnosis of allergic dermatitis be
made and Apoquel considered.
Is Apoquel the only option for treatment of allergies?
By no means is Apoquel the only answer. It makes sense to use
other safe means to control the symptoms of allergies such as
diet, immunotherapy, bathing and omega 3 fatty acids. If one
can prove the patient has a food allergy, there would be no
need for additional medication of any kind. Therefore, when
indicated, a proper food trial with an elimination diet is always
recommended. Remember that serum testing for food allergies
has repeatedly been shown to be inaccurate and essentially
useless. Intradermal or serum testing for environmental allergies and subsequent immunotherapy is strongly recommended.
Immunotherapy offers the potential for “curing” the patient up
to 30% of the time and is a safe product with essentially no
side effects. In those patients not cured, immunotherapy can
help control symptoms of allergies in another 50% of the patients. Bathing and the use of conditioners which contain
ceramides can help restore some of the normal barrier function
to the skin that is so disrupted with allergic dermatitis. Omega
3 fatty acids in proper levels can also reduce some of the
symptoms in up to 40% of the allergic patients. Combinations
of some or all of the above are useful in management of allergic patients when partnered with Apoquel, or as we have in the
past, corticosteroids and cyclosporine.
One of the really cool things about Apoquel is its rapidity of
action. Zoetis completed a study comparing it to IM administered dexamethasone and oral prednisolone and found the
Apoquel had a significantly faster onset of action in pruritus
reduction than either drug. This has held true in my clinical
experience.
What are some contraindications for Apoquel?
Apoquel is labeled for use only in dogs that are greater than
one year of age. It is contraindicated if there is significant bacterial, fungal or viral infection present in the patient. It is logical to avoid a drug that directly affects the immune response in
any animal that has a significant infectious process occurring in
their body. Apoquel has not been approved for use in cats. All
March/April 2014 • WRVS’ Newsletter • 2
Based on the clinical studies there are very few side effects
with Apoquel. Transient diarrhea and vomiting occurred in
<5% of the patients during the trials which approached the
same level in the placebo group. Blood work and urinalysis
were monitored frequently of the patients receiving Apoquel
during the 112 day study and no biochemical abnormalities of
significance were noted.
The big question with regard to side effects is what will happen in 3-5 years or more if a dog is chronically on a drug that
is manipulating part of its immune system. Will these patients
develop chronic infections? Will these patients develop cancer? Will the drug lose its efficacy? Will the body produce other proinflammatory, proallergy or pruritogenic cytokines to
compensate for the low levels of IL-2, 4, 6, 13 and 31? Though
Apoquel looks very promising today we just don’t know what
the future will hold. You can bet that Zoetis and veterinarians
in general will be very diligent to monitor the long term side
effects of this new wonder-drug.