Apoquel is a medication used to control itching and inflammation in dogs, but it may cause side effects in some patients[1].
The most common side effects of Apoquel are:
- Vomiting
- Diarrhea
- Lethargy (low energy)
- Anorexia (loss of appetite)
- Bloodwork changes
These effects are typically mild and often resolve on their own[5][6]. Most reported cases involve short-term gastrointestinal symptoms or decreased activity.
Less common and rarer side effects may include:
- Elevated liver enzymes
- Decreased leukocytes or globulins
- Subcutaneous or dermal masses
- Skin and ear infections
- Urinary tract infections
- Demodicosis (skin infection with Demodex mites)
- Seizures
- Increased thirst or appetite
- Aggression
Rare adverse effects such as bone marrow suppression—which manifests as changes seen on bloodwork rather than outward symptoms—have also been observed, occurring in about 1% of treated dogs[1]. For this reason, bloodwork monitoring is advised 2–3 months after starting therapy.
There is concern that Apoquel, by suppressing immune responses, could increase susceptibility to infections and potentially exacerbate pre-existing cancers or trigger the development of new masses. However, studies have not found a significant increase in neoplasia rates compared to other therapies when used according to label directions[2][5]. Gut microbiome disruption is also discussed by some practitioners, though this is not universally accepted[3].
Precautions:
- Do not use in dogs under 12 months old
- Do not use with serious infections or pre-existing cancers
- Caution in dogs with a history of immune or bone marrow issues
Apoquel should not be used in breeding, pregnant, or lactating dogs, and it has not been evaluated in combination with some other immunosuppressive drugs[4][8].
Overdose can result in more severe symptoms, including persistent vomiting, diarrhea (sometimes with blood), extreme weakness, and collapse, requiring immediate veterinary care[7].
References
- [1] Apoquel side effects- a veterinary dermatologist’s experience
- [2] Safety of the Selective JAK1 Inhibitor Oclacitinib in Dogs – PMC
- [3] Evaluating Apoquel’s Side Effects on Canine Health
- [4] N141345 Apoquel untitled letter – FDA
- [5] Apoquel (oclacitinib tablet): – Fast-Acting and Safe Itch Relief for Dogs
- [6] Apoquel® for Dogs – PetMD
- [7] Apoquel Overdose in Dogs | Critical Steps & When It’s an Emergency
- [8] HH1175303-L22-APOQ-Apoquel Safety Infographic.indd – Zoetis