Lethargy after Pyrantel in dogs

The FDA has received 928 reports of lethargy in dogs after Pyrantel. That is 19% of all reports for this medicine, compared with 11% across reports for all dog medicines, so it is reported unusually often with this medicine.

928Reports

31%Marked serious

15%Recovered

23%Died or euthanised

1 daysTypical onset

How soon it started

Same day

221 48%

1–2 days

107 23%

3–7 days

34 7.4%

1–4 weeks

57 12%

Over a month

43 9.3%

How the animals did

Recovered

134 14%

Recovered with lasting effects

6 0.6%

Still unwell when reported

172 19%

Died

175 19%

Euthanised

42 4.5%

Not known

399 43%

Problems reported at the same time

401 43%

336 36%

243 26%

211 23%

68 7.3%

67 7.2%

66 7.1%

63 6.8%

Age of the animals

Under 1 year

562

1–3 years

151

4–7 years

8–11 years

12+ years

About this medicine

Pyrantel treats roundworms and hookworms.

Questions owners ask

Can Pyrantel cause lethargy in dogs?: 928 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 1 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).

Lethargy with similar medicines

Lethargy after Pyrantel + Sarolaner (Simparica Trio) 3,702 reports · 6.9% of its reports
Lethargy after Febantel + Praziquantel + Pyrantel (Drontal Plus) 651 reports · 9.7% of its reports
Lethargy after Fenbendazole 1,078 reports · 18% of its reports
Lethargy after Praziquantel + Pyrantel 956 reports · 26% of its reports
Lethargy after Praziquantel 148 reports · 13% of its reports

All reported side effects of Pyrantel in dogs · Medicines most reported with lethargy