How does Apoquel work and what is it used for?

Oclacitinib inhibits enzymes involved in itch, inflammation and allergic reactions (Janus-kinase enzymes 1 and 3). These enzymes are involved in pro-inflammatory cytokine signalling (pro-inflammatory cytokines are small proteins that increase the activity of inflammatory cells in the body). By inhibiting these enzymes, oclacitinib suppresses the itch-cascade. 

Oclacitinib is registered for use in dogs predominantly for atopic dermatitis in dogs, but it may also be prescribed for the treatment of the itch associated with other forms of allergic dermatitis (food allergy dermatitis, flea allergy dermatitis and contact dermatitis). It's use in dogs for conditions other than atopic and allergic dermatitis, and it's use in cats is off-label (meaning that it has not been registered in these cases), but it may be prescribed for other conditions as well. In these cases, please follow the directions of your treating Veterinarian closely. 

How is it administered?

Apoquel comes as either a tablet, or a liver-flavoured chew. The chew is usually readily consumed by dogs when offered as a treat. If the chew is not taken voluntarily, it can also be given with a small amount of food or directly into the mouth. If your dog experiences gastrointestinal side effects to this medication, it is recommended to give the tablet or chew with food. 

Apoquel comes in either blister packs or bottles. The tablets and chews are scored, allowing for them to be halved. Please see below for storage instructions for halved tablets and chews. 

How quickly does it work?

Oclacitinib takes effect quickly, usually with a noticeable effect within 24 hours.

It is administered twice daily for 14 days, then once daily ongoing. It is reported anecdotally that some dogs become itchy when changing to once daily dosing. This is usually self-limiting, however if the itching is significant, please contact your veterinarian to discuss the next steps. 

What are the potential side effects of Apoquel?

The most common side effects of Apoquel within the first 16 days of use are:

  • Vomiting
  • Diarrhoea
  • Anorexia
  • Increased drinking
  • Lethargy

Less common side effects include:

  • Increased susceptibility to infection e.g. urinary tract infections, respiratory infections and skin infections 
  • Development of skin lumps, particularly papillomas

Precautions and Contraindications


  • Use in animals intended for breeding, or pregnant or lactating dogs is not recommended as the safety of the medication has not been evaluated in these cases.
  • Since Oclacitinib modulates the immune system, it may increase the susceptibility to infection and the development of papillomas, and may exacerbate cancerous conditions. As such, dogs receiving Apoquel should be monitored for the development of infections and cancerous changes.


  • Not registered for use in dogs under 12 months of age.
  • Not registered for use in dogs under 3kg bodyweight.
  • Should not be used in dogs with evidence of immune suppression such as Cushings Disease or with progressive malignant cancer, as it has not been evaluated in these cases.

Does Oclacitinib interact with other drugs?

The use of Apoquel has not been tested in combination with glucocorticoids, cyclosporine, or other systemic immunosuppressive agents, but the general consensus is that it's use is contraindicated in combination with these medications due to the immunosuppressive effects. Please advise your treating Veterinarian of any other medications and supplements that your pet is taking. 

No drug interactions were observed in field studies where oclacitinib was administered in combination with veterinary medicinal products such as parasiticides, antibiotics and anti-inflammatories, as well as vaccines for canine parvovirus and canine distemper virus. However, the immune response to the modified live vaccine for canine parainfluenza was reduced, though the clinical significance of this reduction is unclear.

Can Apoquel be used during a food allergy trial? 

Apoquel tablets can be used during a food allergy trial, however it is important to follow the instructions of your treating veterinarian closely. It is recommended that the chewable form should not be used during a food allergy trial as the ingredients may interfere with the trial. 

Storage and Handling

You should wash your hands immediately after handling Oclacitinib chews or tablets. 

Apoquel tablets and chews should be stored at room temperature below 25 degrees celsius. 

If from a bottle, half-tablets should be stored in the bottle with cap sealed and used within 60 days. If from a blister pack, half tablets should be stored in the opened blister and the blister returned to the carton, and these half-tablets should be used within 2 days.

Accidental ingestion of oclacitinib can be harmful for children. To avoid accidental ingestion, administer the tablet to your dog immediately after removal from the package, and observe your dog closely to ensure that the entire dose has been consumed. Keep out of reach and sight of children.


The recommended dose of Apoquel is 0.4 - 0.6 mg/kg bodyweight, administered twice daily for up to 14 days, and then administered once daily for maintenance therapy. It is crucial that you follow your Veterinarian's specific instructions regarding dosage for your individual pet. 

What should I do if my dog misses a dose?

If you miss giving your dog a dose of Apoquel, give it as soon as you remember.  However, if it is close to the time for the next dose, skip the missed dose and resume the dosing schedule as normal - do not give two doses at once.

Stopping Apoquel

If your veterinarian advises for your dog to stop taking Apoquel, this can be done without the need for a tapering off period. Any cessation or change to your dog's medication should only be done under the close supervision and recommendation of your treating Veterinarian. 

What should I do if my dog has taken too many Apoquel tablets?

If you know or suspect your dog has had an overdose of Oclacitinib, we recommend that you contact your treating veterinarian or emergency veterinary hospital immediately. 

Importance of Veterinary Monitoring

Field studies on Oclacitinib noted a slight reduction in white blood cell counts, as well as an increase in blood cholesterol levels in some dogs. For this reason, and also due to the other possible side effects, regular veterinary monitoring is important to track blood changes, and check for evidence of infection,  cancerous changes and skin growths. 

Alternative and Related Medications

There are no direct alternatives to Apoquel, and as the safety and efficacy of compounded forms of Oclacitinib has not been evaluated, they are not recommended. Related medications include:

  • Corticosteroids (e.g. prednisolone)
  • Cyclosporin (Atopica)
  • Lokivetmab (Cytopoint)
  • Antihistamines