Weight loss after Fenbendazole in dogs

The FDA has received 111 reports of weight loss in dogs after Fenbendazole. That is 1.9% of all reports for this medicine, compared with 1.7% across reports for all dog medicines.

111Reports

54%Marked serious

3.6%Recovered

35%Died or euthanised

7 daysTypical onset

How soon it started

Same day

11 17%

1–2 days

10 16%

3–7 days

12 19%

1–4 weeks

15 24%

Over a month

15 24%

How the animals did

Recovered

4 3.6%

Still unwell when reported

29 26%

Died

24 22%

Euthanised

15 14%

Not known

39 35%

Problems reported at the same time

62 56%

47 42%

44 40%

39 35%

38 34%

17 15%

16 14%

15 14%

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 weight loss in dogs?: 111 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 7 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).

Weight loss with similar medicines

Weight loss after Pyrantel + Sarolaner (Simparica Trio) 317 reports · 0.6% of its reports
Weight loss after Febantel + Praziquantel + Pyrantel (Drontal Plus) 68 reports · 1.0% of its reports
Weight loss after Pyrantel 93 reports · 1.9% of its reports
Weight loss after Praziquantel + Pyrantel 46 reports · 1.2% of its reports

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