Blood in stool after Fenbendazole in dogs

The FDA has received 60 reports of blood in stool in dogs after Fenbendazole. That is 1.0% of all reports for this medicine, compared with 0.6% across reports for all dog medicines, so it is reported unusually often with this medicine.

60Reports

20%Marked serious

1.7%Recovered

28%Died or euthanised

14 daysTypical onset

How soon it started

Same day

2 13%

1–2 days

3 20%

3–7 days

1 6.7%

1–4 weeks

3 20%

Over a month

6 40%

How the animals did

Recovered

1 1.7%

Still unwell when reported

3 5.0%

Died

10 17%

Euthanised

7 12%

Not known

39 65%

Problems reported at the same time

26 43%

18 30%

18 30%

17 28%

14 23%

11 18%

9 15%

7 12%

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 blood in stool in dogs?: 60 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 14 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).

Blood in stool with similar medicines

Blood in stool after Pyrantel + Sarolaner (Simparica Trio) 43 reports · 0.1% of its reports
Blood in stool after Febantel + Praziquantel + Pyrantel (Drontal Plus) 27 reports · 0.4% of its reports
Blood in stool after Pyrantel 77 reports · 1.6% of its reports
Blood in stool after Praziquantel + Pyrantel 31 reports · 0.8% of its reports

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