Loose stool after Fenbendazole in dogs

131 reports to the FDA describe loose stool in dogs given Fenbendazole. That is 2.2% of all reports for this medicine, compared with 0.9% across reports for all dog medicines, so it is reported unusually often with this medicine.

131Reports

38%Marked serious

21%Recovered

11%Died or euthanised

4 daysTypical onset

How soon it started

Same day

18 21%

1–2 days

17 20%

3–7 days

15 17%

1–4 weeks

15 17%

Over a month

21 24%

How the animals did

Recovered

26 20%

Recovered with lasting effects

1 0.8%

Still unwell when reported

43 33%

Died

9 6.9%

Euthanised

5 3.8%

Not known

47 36%

Problems reported at the same time

51 39%

40 31%

37 28%

27 21%

22 17%

14 11%

Didn't work as expected

12 9.2%

Liver problems

12 9.2%

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 loose stool in dogs?: 131 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 4 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).

Loose stool with similar medicines

Loose stool after Pyrantel + Sarolaner (Simparica Trio) 329 reports · 0.6% of its reports
Loose stool after Febantel + Praziquantel + Pyrantel (Drontal Plus) 145 reports · 2.2% of its reports
Loose stool after Pyrantel 84 reports · 1.8% of its reports
Loose stool after Praziquantel + Pyrantel 146 reports · 4.0% of its reports

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