Oclacitinib (Apoquel) for Cats: Dosing and Safety
By Dr. Zubair Khalid, DVM, MS, PhD ·
Oclacitinib for cats dosage is not a fixed number you can look up and use at home. It is an off-label medication in cats, meaning a veterinarian must decide the dose based on your cat's weight, condition, and lab work.
This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Oclacitinib (brand name Apoquel) is FDA-approved for dogs only, so any use in cats is off-label and requires a veterinarian's prescription [1][2].
- Many cats improve on oclacitinib, but response is not guaranteed. In one large review, about 59% of cats had their skin signs controlled [3].
- Common side effects include vomiting, diarrhea, lethargy, and appetite loss. Serious problems include kidney injury after large overdoses [4][5][6].
- Keep the bottle locked away. Chewable Apoquel tablets have caused a sharp rise in accidental pet poisonings since late 2023 [5].
What Is Oclacitinib and Why Do Veterinarians Use It in Cats?
Oclacitinib maleate is a Janus kinase (JAK) inhibitor sold as Apoquel by Zoetis. The FDA approved it in 2013 for dogs with allergic itch and atopic dermatitis [2]. It is not approved for cats, and the manufacturer does not recommend feline use because clinical trial data are limited [1].
Even so, veterinarians prescribe it off-label for cats with allergic skin disease and severe itching. Off-label means a licensed veterinarian uses an approved drug in a species or condition the label does not cover. This is legal and common in veterinary medicine when the veterinarian believes the benefits outweigh the risks.
Published feline reports describe use for allergic pruritus, eosinophilic skin disease, and other inflammatory dermatoses. In one case report, a diabetic cat with severe facial eosinophilic furunculosis and vasculitis improved quickly on short-term oclacitinib when steroids were a poor choice because of the cat's diabetes [7]. That is a single case, so it does not prove the drug works for every cat with a similar problem.
If your cat has been itching for weeks and steroids have not helped, or your cat cannot safely take steroids, your veterinarian may discuss oclacitinib as one option. Other options exist, including cyclosporine, antihistamines, and immune-modulating drugs. The choice depends on your cat's diagnosis, blood work, and other medications.
How Oclacitinib Works
Oclacitinib blocks Janus kinase enzymes, especially JAK1. These enzymes sit inside cells and pass along signals from cytokines, the chemical messengers that drive itching and inflammation. By blocking JAK1, the drug turns down the itch signal and some of the inflammatory response [2].
This is different from steroids, which act broadly across many body systems. Oclacitinib is more selective, which is one reason it is attractive for cats that cannot tolerate steroids. The trade-off is that cats appear to need higher doses than dogs and may have less of a safety margin [1].
The drug starts working quickly in many dogs, often within a day or two. Cats may respond on a similar timeline, but published feline data are much thinner. In a long-term study of 14 cats, 7 cats had their maintenance dose cut by at least half, usually after about 15 days of treatment [8]. That suggests some cats can taper down once their itch is controlled, but only under veterinary direction.
Oclacitinib for Cats Dosage: What Owners Should Know
Who Decides the Dose
Your veterinarian decides the dose. Never split, crush, or adjust tablets on your own. The dose depends on your cat's weight, the severity of the skin problem, kidney and liver values, and what other drugs your cat takes.
What Published Doses Look Like
In a review of 238 cats, the average starting dose was 1.89 mg/kg per day [3]. Cats that responded were often started on twice-daily dosing at an average of 1.85 mg/kg per day, while others did well on once-daily dosing at an average of 1.05 mg/kg per day [3]. A separate long-term study of 14 cats reported a median starting dose of 1.1 mg/kg every 12 hours [8].
These are averages from medical records, not dosing instructions. Your cat's dose may be higher or lower. Do not use these numbers to dose your cat at home.
How It Is Given
Oclacitinib comes as film-coated tablets and, since October 2023, as chewable tablets [5][2]. Chewables are flavored and easy for pets to find, which is exactly why accidental ingestions have risen. Give the tablet with or without food unless your veterinarian says otherwise. If your cat spits out the pill, do not give a second full dose without asking your veterinarian first.
Missed Doses
If you miss a dose, give it when you remember unless it is almost time for the next one. Then skip the missed dose and go back to your normal schedule. Never double up to catch up. Call your veterinarian if you are unsure.
Side Effects of Oclacitinib in Cats
The table below separates common problems from serious ones. Report any side effect to your veterinarian, even if it seems mild.
| Side effect | How common or serious | What to do |
|---|---|---|
| Vomiting, diarrhea, appetite loss, lethargy | Common in dogs and reported in cats, usually mild [4][5][2] | Call your veterinarian if it lasts more than a day or your cat stops eating |
| Eye changes (elevated third eyelid, squinting) | Reported in cats after accidental overdose [4] | Contact your veterinarian or poison control right away |
| Mild blood test changes (cholesterol, liver enzymes, creatinine, glucose) | Seen in long-term feline treatment, often mild and transient [8] | Keep scheduled monitoring blood work |
| Platelet or white blood cell changes | Limited and temporary in some cats [8] | Your veterinarian will track these on lab work |
| Acute kidney injury | Serious, seen after large overdoses above 100 mg/kg [6] | Emergency care immediately |
| Neurologic, heart, or multi-organ signs | Serious, reported in overdose cases [5] | Emergency care immediately |
For a deeper look at what owners report, see What Are the Side Effects of Apoquel for Cats?.
Common Side Effects
The most frequently reported adverse events in dogs on oclacitinib are diarrhea, anorexia, and lethargy [2]. Feline reports describe similar problems, plus occasional vomiting [4][5]. Many of these signs are mild and go away. Some cats have non-dermatologic illnesses during treatment that resolve without changing the oclacitinib schedule [8].
Serious Side Effects
Serious problems are mostly tied to overdose. Three cats that swallowed more than 100 mg/kg developed severe acute kidney injury, and two of the three died or were euthanized [6]. A larger poison center review found multi-system involvement in symptomatic cats and dogs, including neurologic, gastrointestinal, cardiovascular, kidney, liver, and eye signs [5]. These are not typical reactions to correct dosing, but they show how narrow the margin can be when too much is given.
Who Should Not Take Oclacitinib
Oclacitinib is not for every cat. Your veterinarian may avoid it or use extra caution if your cat has:
- Kidney disease or a history of kidney problems
- Liver disease
- A weakened immune system or active infection
- A history of cancer
- A known allergy to oclacitinib or tablet ingredients
Cats with diabetes need special thought. One diabetic cat was treated successfully with short-term oclacitinib when steroids were not an option, but that is one case and does not mean the drug is safe for every diabetic cat [7].
Drug Interactions
Tell your veterinarian about every medication, supplement, and topical product your cat receives. This matters most for:
- Other immunosuppressive drugs, such as cyclosporine or steroids
- NSAIDs, including robenacoxib (see Onsior Robenacoxib for Cats: Feline NSAID Safe Dosing Protocol)
- Heart medications such as atenolol (see Atenolol Cat Heart Dose: Beta Blocker Feline Heart Protocol)
- Appetite stimulants such as mirtazapine (see Mirtazapine Appetite Stimulant: Dose for Cats and Dogs Guide)
Your veterinarian will weigh the risks and may adjust doses or choose a different drug.
Overdose: When to Call a Veterinarian or Poison Control
An overdose is a medical emergency. Signs can include vomiting, diarrhea, lethargy, not eating, eye changes such as a raised third eyelid or squinting, and in severe cases kidney failure [4][5][6].
If you think your cat ate extra tablets, call for help right away. Do not wait for symptoms.
- Pet Poison Helpline: 855-764-7661
- ASPCA Animal Poison Control Center: 888-426-4435
Bring the bottle with you to the veterinarian so they know the strength and how many tablets are missing. If you have multiple pets, take all of them for evaluation if you are not sure who ate the pills. That is what the poison specialists recommended in one reported case involving five cats [4].
Treatment for overdose is supportive. It may include fluids, medications for nausea, and monitoring of kidney and other organ function. One cat in a case series recovered fully with intensive care, while two others did not survive [6]. Quick action gives your cat the best chance.
Limitations and When to Contact a Veterinarian
Oclacitinib use in cats is off-label, and the evidence base is smaller than it is for dogs [1]. Individual cases need a veterinarian who knows your cat's history, lab work, and other medications. No article can replace that.
Contact your veterinarian the same day if your cat:
- Vomits more than once or has diarrhea for more than a day
- Refuses food for more than 24 hours
- Seems unusually tired or weak
- Develops squinting, a raised third eyelid, or other eye changes
- Has any new symptom after starting or changing the dose
Go to an emergency clinic now if your cat:
- Ate more tablets than prescribed
- Collapses, has trouble breathing, or seems disoriented
- Stops producing urine or strains to urinate
- Has a seizure
Keep routine recheck visits, including blood work. Long-term feline treatment has been linked to mild, often temporary changes in cholesterol, liver enzymes, creatinine, glucose, platelets, and white blood cells [8]. Monitoring catches problems early.
Frequently Asked Questions
Is oclacitinib safe for cats?
It can be used safely in some cats under veterinary supervision, but it is off-label and cats appear to have less therapeutic safety than dogs [1]. Safety depends on the dose, your cat's organ function, and what other drugs your cat takes. Regular monitoring helps catch problems early.
How long does oclacitinib take to work in cats?
Many cats show improvement within the first couple of weeks, and some respond faster. In a long-term study, several cats had their dose reduced by at least half after about 15 days [8]. If you see no improvement after a few weeks, your veterinarian may reconsider the diagnosis or change treatment.
Can I give my cat my dog's Apoquel?
No. Dogs and cats are different species with different dosing needs, and cats may need higher doses with less safety margin [1]. Giving your cat a dog's tablet could underdose or overdose your cat. Always use a prescription written for your cat.
What happens if my cat eats extra Apoquel tablets?
Large overdoses can cause severe acute kidney injury and multi-organ illness, and some cats do not survive [5][6]. Call Pet Poison Helpline at 855-764-7661 or ASPCA Animal Poison Control at 888-426-4435 right away, then follow their instructions. Do not wait for symptoms to appear.
Does oclacitinib cure cat allergies?
No. Oclacitinib controls itching and inflammation while your cat takes it, but it does not cure the underlying allergy. Most cats need ongoing treatment plus other measures such as flea control, diet changes, or environmental management. Your veterinarian will build a plan that fits your cat's specific triggers.
Related Articles
- What Are the Side Effects of Apoquel for Cats?
- Onsior Robenacoxib for Cats: Feline NSAID Safe Dosing Protocol
- Atenolol Cat Heart Dose: Beta Blocker Feline Heart Protocol
- Mirtazapine Appetite Stimulant: Dose for Cats and Dogs Guide
- Cat Anxiety Medication: What You Need to Know
- Can You Give Your Cat Benadryl? Dosage and Safety Guide
- Mirtazapine for Cats: Side Effects, Dosage, and Safety
- Sileo for Cats: Dosage, Safety, and What to Expect
- Is Fipronil Safe for Cats? Dosing and Risks
References
- Oclacitinib in dogs - Janus kinase inhibition in veterinary dermatology. Tierarztliche Praxis. Ausgabe K, Kleintiere/Heimtiere, 2025.
- Safety of the Selective JAK1 Inhibitor Oclacitinib in Dogs. Journal of veterinary pharmacology and therapeutics, 2025.
- A Retrospective Case Series Reporting the Clinical Efficacy and Adverse Events of Oclacitinib Administration for Skin Disease in 238 Cats. Veterinary dermatology, 2026.
- Toxin Calls Regarding Apoquel Increase. Pet Poison Helpline.
- Multisystemic Consequences Following Oclacitinib Maleate (Apoquel®) Overdose Ingestion in Cats and Dogs. Journal of medical toxicology : official journal of the American College of Medical Toxicology, 2025.
- Severe Toxicosis Secondary to Accidental Oclacitinib Ingestion in Three Cats. Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001), 2026.
- Oclacitinib Treatment and Surgical Management in a Case of Periocular Eosinophilic Furunculosis and Vasculitis with Secondary Eyelid Fusion in a Diabetic Cat. Veterinary sciences, 2025.
- Long-term oclacitinib administration for the control of feline allergic pruritus: A retrospective study of 14 client-owned cats. The Canadian veterinary journal = La revue veterinaire canadienne, 2025.