Health & Medical

Ask a Vet: What’s Apoquel and is it Safe?

Apoquel for Itchy Dogs | Vanillapup

Apoquel is a lifesaver for Latte. An anti-itch drug, Apoquel works fast and well for most dogs. Yet, why are its safety and usefulness widely challenged?

Q. Can you tell me more about how Apoquel works and what are the side effects? Some online articles say this drug is harmful so I don’t know whether my itchy dog should try it.

Apoquel treats itching by inhibiting specific enzymes called Janus Kinases (JAK). JAK produces molecules in the body called cytokines that contribute to inflammatory and itch responses.

By reducing the production of these cytokines, itching is thus reduced.

Only an anti-itch drug

Apoquel does not treat skin infections caused by bacteria (pimples), yeast, or parasites, such as Demodex. Such infections need specific topical or oral antibiotics, antifungal, or antiparasitic treatment.

Side effects

The common adverse reactions to Apoquel listed by the manufacturer include:

  • lethargy
  • vomiting
  • diarrhoea
  • loss of appetite

In one study of 152 Apoquel-treated dogs and 147 placebo-treated dogs that did not receive the active drug ingredient, the incidence of these adverse reactions was generally low at 2.0 – 4.6%.

The report shows that the side effects occurred within the first 16 days of treatment. But they were mostly resolved with continued Apoquel treatment.

Most of these reactions, such as lethargy, vomiting, and diarrhoea were generally similar in both groups (dogs that received the drug and those that received a placebo).

Dogs receiving treatment also had a reduction in some white cell counts. However, they were on average still within normal reference ranges.

Not for all

The manufacturer advises against the use of Apoquel in dogs with serious infections.

Also, its use may increase susceptibility to infections, including Demodex skin infections, and exacerbate existing or underlying cancers.

Nonetheless, all medications have their own potential adverse reactions, contraindications, and precautions.

A new drug

Apoquel has been in the veterinary market in the USA since 2014. Hence, long-term efficacy and safety data is still lacking.

Having said that, it is so far a promising treatment option for itchy dogs.

Dogs generally have a good and fast response to Apoquel without the relatively high incidence of short- and long-term side effects of steroids, the common alternative.

Side effects of steroid treatment include:

  • increased drinking, appetite, and urination
  • fatty liver disease
  • diabetes
  • thinning of the skin

Tackling underlying causes

As itching and skin rash are commonly caused by allergies, it is important not to only rely on Apoquel or other anti-itch medications to manage the condition.

You need to work with your vet to investigate the underlying causes of the allergy (e.g. food or environmental), as discussed in greater detail in my previous post.

Dogs should only be on anti-itch medications long-term after you and your vet have investigated and managed the allergies.

That is because some of these dogs may not need Apoquel once you have managed the allergies via avoidance of the allergen and/or immunotherapy treatment for environmental allergens.

Your vet may recommend Apoquel only after comparing the potential risks and benefits of Apoquel and other treatment options, such as steroids or cyclosporine for your dog.

Therefore, please see your trusted vet for further assessment and advice on whether Apoquel is suitable for your dog at this stage.

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Photo credit: luckyno3 via / CC BY-NC

Dr. Brian Loon on Facebook
Dr. Brian Loon
Principal Veterinary Surgeon at Amber Vet
BSc. BVMS (Hons) (Murdoch), Certificate Veterinary Acupuncture (IVAS)

Dr. Brian Loon graduated from Murdoch University, Western Australia in 2007 and has since been practising as a small animal veterinarian in Singapore. His areas of special interest include diagnostic ultrasonography, endoscopy, and minimally invasive (keyhole) surgery (laparoscopy).

He is also certified in Veterinary Acupuncture with the International Veterinary Acupuncture Society (IVAS) and a certified and registered member of PennHIP, an internationally known modality for diagnosing hip dysplasia in cats and dogs.


  1. Shona

    February 10, 2017 at 4:40 pm

    My dog took it for a couple of months and it stopped working. Back to the drawing board. 🙁

    • Vanillapup

      February 11, 2017 at 12:04 am

      Oh that’s sad to hear. It’s still working for Latte and we are trying to reduce the frequency with time. Did Dr. Gino offer alternative solutions?

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