Behaviour change after Praziquantel in cats

The FDA has received 159 reports of behaviour change in cats after Praziquantel. That is 9.6% 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.

159Reports

23%Marked serious

35%Recovered

5.7%Died or euthanised

Same dayTypical onset

How soon it started

Same day

76 58%

1–2 days

24 18%

3–7 days

12 9.2%

1–4 weeks

11 8.5%

Over a month

7 5.4%

How the animals did

Recovered

55 35%

Still unwell when reported

23 14%

Died

8 5.0%

Euthanised

1 0.6%

Not known

72 45%

Problems reported at the same time

38 24%

32 20%

23 14%

18 11%

17 11%

Restlessness or agitation

16 10%

Vocalising

14 8.8%

Didn't stop worms

14 8.8%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Praziquantel treats tapeworms.

Questions owners ask

Can Praziquantel cause behaviour change in cats?: 159 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 the same day 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 Emodepside + Praziquantel (Profender) 385 reports · 6.7% of its reports
Behaviour change after Praziquantel + Pyrantel 88 reports · 7.0% of its reports
Behaviour change after Pyrantel 28 reports · 5.0% of its reports

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