Is Atenolol (Tenormin) Safe for Cats?
Why it’s a problem
Cats are small, so a single human tablet can be a substantial overdose that slows the heart severely. Beta-blocker toxicity in cats has been reported to cause profound lethargy, low blood pressure, and collapse. Cats with heart disease — often the reason atenolol exists in a household — are extra vulnerable.
How to keep your pet safe
Store atenolol where a cat cannot tip the bottle, and never leave tablets loose on a counter. Heart medication for a cat should only come from a veterinary prescription.
Warning signs to watch for
Profound lethargy, weakness, wobbliness, vomiting, pale gums, very slow heart rate; severe cases: collapse, fainting, cold paws and ears.
When to call the vet
Call your veterinarian or a pet poison hotline promptly — a slow heart rate may need clinical monitoring for hours. Report the tablet strength and your cat’s weight.
Common questions
My cat swallowed one of my beta blockers — is it dangerous?
Yes — one human tablet can severely slow a small cat’s heart. Call your vet or a pet poison hotline immediately rather than waiting for symptoms.
My vet prescribed atenolol for my cat’s heart — is that the same?
Veterinary use involves tiny, calculated doses with monitoring. Never share your own tablets — human strengths can dangerously overdose a cat.
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).