Malaise after Fenbendazole in dogs

The FDA has received 32 reports of malaise in dogs after Fenbendazole. That is 0.5% of all reports for this medicine, compared with 0.4% across reports for all dog medicines.

32Reports

53%Marked serious

13%Recovered

28%Died or euthanised

2 daysTypical onset

How soon it started

Same day

2 13%

1–2 days

6 40%

3–7 days

1 6.7%

1–4 weeks

3 20%

Over a month

3 20%

How the animals did

Recovered

4 13%

Still unwell when reported

7 22%

Died

9 28%

Not known

12 38%

Problems reported at the same time

14 44%

11 34%

10 31%

9 28%

6 19%

4 13%

4 13%

4 13%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Fenbendazole treats intestinal worms and some other parasites.

Questions owners ask

Can Fenbendazole cause malaise in dogs?: 32 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 2 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).

Malaise with similar medicines

Malaise after Pyrantel + Sarolaner (Simparica Trio) 90 reports · 0.2% of its reports
Malaise after Pyrantel 58 reports · 1.2% of its reports
Malaise after Praziquantel + Pyrantel 20 reports · 0.5% of its reports

All reported side effects of Fenbendazole in dogs · Medicines most reported with malaise