Behaviour change after Fluoxetine in cats

31 reports to the FDA describe behaviour change in cats given Fluoxetine. That is 13% of all reports for this medicine, compared with 5.4% across reports for all cat medicines, so it is reported unusually often with this medicine.

31Reports

32%Marked serious

29%Recovered

9.7%Died or euthanised

27 daysTypical onset

How soon it started

Same day

5 23%

1–2 days

3 14%

3–7 days

0 0.0%

1–4 weeks

4 18%

Over a month

10 45%

How the animals did

Recovered

5 16%

Recovered with lasting effects

4 13%

Still unwell when reported

10 32%

Died

1 3.2%

Euthanised

2 6.5%

Not known

9 29%

Problems reported at the same time

Lethargy

8 26%

Loss of appetite

6 19%

Wobbliness (ataxia)

5 16%

Didn't work as expected

4 13%

Vomiting

4 13%

Itching

4 13%

Dilated pupils

4 13%

Intentional misuse

4 13%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Fluoxetine treats anxiety and behaviour problems.

Questions owners ask

Can Fluoxetine cause behaviour change in cats?: 31 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 27 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Behaviour change with similar medicines

Behaviour change after Gabapentin 201 reports · 10% of its reports

All reported side effects of Fluoxetine in cats · Medicines most reported with behaviour change