Flea, tick & worm products · cat safety
Is ivermectin toxic to cats?
Severe
No — don't give a cat ivermectin meant for people (Ivermectol) or for cattle, horses or dogs. Vets use some of these medicines in cats, but only at a carefully worked-out cat dose; overdoses cause wide pupils, sudden blindness, wobbliness, tremors and coma. Go to a vet now.
Why severe: Wrong-strength ivermectin — human tablets or farm products — causes blindness, tremors and coma in cats; thin cats were hit hardest in one series.
- Name
- Ivermectin (human tablets and livestock dewormers)also Ivermectol, Ivermectin injection for cattle, Horse and cattle dewormer paste or pour-on, Avermectins
- Hindi
- आइवरमेक्टिन
What counts
Ivermectin tablets for people, cattle and buffalo injections, pour-ons and horse dewormer pastes, and related farm products (doramectin, moxidectin).
What's in it
Ivermectin and related avermectins; in an overdose they reach the brain and depress the nervous system (Pet Poison Helpline).
Brands it hides in
- Ivermectol and other human ivermectin tablets
- Cattle and buffalo ivermectin injections from the agri or vet shop
- Horse and cattle dewormer pastes and pour-ons
Symptoms to watch for
- Wide pupils, sudden blindness
- Wobbliness, tremors
- Drooling
- Disorientation, unresponsiveness
- Seizures
- Slow breathing, coma
Within hours: five cats given horse paste in their ears were ill about 12 hours later (JAVMA 2015). Signs lasted about 48 hours in a series of 20 overdosed cats (Jourdan et al. 2015).
What to do — now
Go to a vet now. Vets can treat ivermectin poisoning, and blindness from it often recovers (JAVMA 2015).
- Take the tablet strip, vial or tube.
- Don't make your cat vomit at home unless a vet tells you to.
- Never inject or drop a farm or human ivermectin product into a cat yourself — not even for mange or ear mites.
Where Indian cats meet it
Ivermectin tablets turn up in Indian medicine boxes and cattle injections are cheap at agri shops, so they sometimes get used 'for mange' on street and pet cats without a vet's dose.
Myth or fact
Myth“Ivermectin is safe for cats — vets use it”
FactThe dose is everything: cats overdosed by mistake developed tremors, blindness and coma (Jourdan et al. 2015; Meekins et al. 2015). Only a vet can work out a cat dose.
Cat-safe swap: Ask your vet for a cat-labelled treatment for mange, ear mites or worms.
Sources
- Pet Poison Helpline: Ivermectin
- Meekins et al. 2015, JAVMA: ivermectin toxicosis and blindness in five cats (PubMed)
- Jourdan et al. 2015, JVECC: 20 cats accidentally overdosed with ivermectin (PubMed)
Facts last checked
General information for cat parents, not a diagnosis or a treatment plan. The facts come from ASPCA, Pet Poison Helpline, International Cat Care, the Merck Veterinary Manual and the other sources listed on every page — and we say so when the evidence comes from dogs or people. If your cat may have eaten something harmful, call your vet.