Is Antidepressants (SSRIs) toxic to cats?
No. Human antidepressants — especially SSRIs like fluoxetine, sertraline, and citalopram — can cause serotonin syndrome in cats. Ingestions are genuine emergencies.
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Key facts
- Verdict: No — dangerous to cats. Antidepressants (SSRIs) should never be given deliberately.
- Category: Human prescription
- Onset: Signs can start 0–4 hours — see the full timeline below.
- If it's already happened: Call your vet now, or the Animal PoisonLine on 01202 509000 (24/7, charges apply) — see the emergency steps below.
If your cat has just eaten antidepressants (ssris)
- Note the drug name, strength, and number of tablets eaten.
- Call your vet or emergency vet immediately.
- If you can't reach a vet, call Animal PoisonLine (01202 509000) — paid triage, 24/7.
What's the full picture?
SSRIs (selective serotonin reuptake inhibitors) and related antidepressants such as SNRIs work by increasing the amount of serotonin available in the brain. In cats, whose bodies are far smaller and process drugs differently to humans, this same mechanism can push serotonin levels well beyond a safe range, producing a cluster of effects known as serotonin syndrome. It affects the nervous system, muscles, and the body's temperature control, and it can progress quickly without treatment. Because these medications are so widely prescribed across the UK, they are among the most common human drugs involved in accidental pet poisonings.
A realistic exposure at home usually involves a dropped tablet, a pill organiser left on a bedside table or kitchen counter, or a handbag or dosette box a cat has managed to get into. Even a single tablet intended for an adult human dose can represent a large relative dose for a cat weighing only 4–5kg, so there's no such thing as a 'safe small amount' to wait and see about — any suspected ingestion should be treated as urgent.
It's worth knowing that vets do sometimes prescribe fluoxetine or similar drugs to cats for behavioural conditions such as severe anxiety or inappropriate urination, but always at a very different, carefully calculated dose and formulation designed for cats. If your cat is already on a prescribed feline dose of an SSRI, that's not a reason to assume your own tablets are any safer — double-dosing from a human tablet on top of a feline prescription carries the same overdose risk as an entirely separate cat getting into your medication.
Signs typically begin within a few hours of ingestion and can include agitation, tremors, vocalising, a racing heart, dilated pupils, and a dangerously high body temperature, progressing to seizures in more severe cases. Treatment at the vet usually involves inducing vomiting if caught early enough, activated charcoal to limit further absorption, sedation to control agitation and tremors, and active cooling if the temperature is elevated. With prompt veterinary treatment most cats recover fully; the main determinant of outcome is how quickly treatment starts after ingestion.
Symptoms to watch for
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Questions owners ask
My cat just licked a dropped tablet — is that dangerous?
Treat it as a vet call regardless of how small the exposure looked. Even a partial tablet can represent a significant dose for a cat's body weight, and it's much easier to manage early with a vet's guidance than after signs have started.
Do vets ever prescribe antidepressants to cats?
Yes, low-dose fluoxetine and similar medications are sometimes used for feline anxiety or behavioural issues, but always at a feline-specific dose set by a vet. This isn't a reason to think human tablets are safe — the doses aren't comparable.
What if I don't know exactly how many tablets are missing?
Give the vet your best estimate along with the drug name and strength from the packet. They'll usually plan for the worst-case number to be safe, so an approximate count is still very useful.
How is serotonin syndrome treated at the vet?
Depending on how soon after ingestion your cat is seen, treatment can include inducing vomiting, activated charcoal, sedatives to control tremors and agitation, and active cooling for a raised temperature, along with monitoring on IV fluids until signs settle.
A lockable medicine box is the simplest way to keep human tablets out of reach of a curious cat.
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Related
Sources referenced for this guidance
- Veterinary Poisons Information Service (VPIS) — UK clinical toxicology reference used by vets
- International Cat Care — feline-specific clinical guidance
- BSAVA — British Small Animal Veterinary Association reference materials
- Merck Veterinary Manual — professional veterinary reference
About this guidance
Every entry on this site is compiled from published UK veterinary toxicology sources — International Cat Care, Veterinary Poisons Information Service (VPIS) references, RCVS-registered practice materials, and peer-reviewed feline medicine literature. Where the evidence is mixed, we err on the cautious side because cats are unusually sensitive to many common substances that are harmless to humans and even to dogs.
This is general information written for UK cat owners. It is not personalised veterinary advice for your specific cat, their age, weight, medical history, or the exact exposure you're dealing with. If your cat has eaten something or is unwell, call your vet first. The Animal PoisonLine on 01202 509000 is available 24/7 for a small fee and can tell you whether an emergency visit is needed.
Entries are reviewed and updated as new research emerges. Spotted an error? Let us know — corrections are investigated and applied within 24 hours. For more context on how we work, see about and our full disclaimer.
Last reviewed: · By the What Can My Cat Eat? editorial team