Is Allopurinol (Zyloprim) Safe for Cats?
Why it’s a problem
Allopurinol sees limited off-label use in cats, but human tablets are much stronger than what a vet would calculate for a small cat. Ingestion most often causes gastrointestinal upset, and cats with kidney disease handle the drug poorly. There is no home scenario in which a cat should eat a person’s gout medication.
How to keep your pet safe
Store allopurinol in a closed cabinet and pick up dropped tablets immediately — cats bat small pills across the floor before eating them. Never split your own medication where a cat can reach the pieces. If a cat needs urinary stone management, a vet must do the dosing.
Warning signs to watch for
Vomiting, drooling, diarrhea, loss of appetite, hiding, lethargy.
When to call the vet
Call your veterinarian or a pet poison hotline after any confirmed or suspected ingestion, and have the tablet strength handy. Do not induce vomiting at home. Most cats need monitoring and supportive care rather than dramatic measures, but a professional should decide.
Common questions
Is allopurinol poisonous to cats?
It is not among the most deadly human drugs, but it can cause real stomach upset and is riskier for cats with kidney disease. Any swallowed tablet warrants a call to your vet or a pet poison hotline.
My vet mentioned allopurinol for my cat — why is eating my own pills different?
Veterinary use involves a feline-specific dose, formulation, and monitoring. Human tablets are far stronger than what a vet would calculate, so an unsupervised dose is unpredictable.
More medications hazards for cats
This page is general educational information, not a substitute for professional veterinary advice. Every pet is different — if your animal ate or touched something concerning, contact your veterinarian or a pet poison hotline right away. In the US: Pet Poison Helpline (855) 764-7661, ASPCA Animal Poison Control (888) 426-4435 (fees may apply).