Seizures after Fenbendazole in dogs

The FDA has received 185 reports of seizures in dogs after Fenbendazole. That is 3.1% of all reports for this medicine, compared with 4.4% across reports for all dog medicines.

185Reports

74%Marked serious

21%Recovered

26%Died or euthanised

1 daysTypical onset

How soon it started

Same day

42 34%

1–2 days

31 25%

3–7 days

16 13%

1–4 weeks

22 18%

Over a month

12 9.8%

How the animals did

Recovered

37 20%

Recovered with lasting effects

2 1.1%

Still unwell when reported

45 24%

Died

27 15%

Euthanised

22 12%

Not known

52 28%

Problems reported at the same time

49 26%

42 23%

40 22%

29 16%

28 15%

26 14%

21 11%

16 8.6%

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 seizures in dogs?: 185 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).

Seizures with similar medicines

Seizures after Pyrantel + Sarolaner (Simparica Trio) 4,687 reports · 8.8% of its reports
Seizures after Febantel + Praziquantel + Pyrantel (Drontal Plus) 108 reports · 1.6% of its reports
Seizures after Pyrantel 229 reports · 4.8% of its reports
Seizures after Praziquantel + Pyrantel 96 reports · 2.6% of its reports

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