Eye or vision problems after Fenbendazole in dogs

The FDA has received 47 reports of eye or vision problems in dogs after Fenbendazole. That is 0.8% of all reports for this medicine, compared with 0.7% across reports for all dog medicines.

47Reports

40%Marked serious

23%Recovered

11%Died or euthanised

1 daysTypical onset

How soon it started

Same day

6 32%

1–2 days

7 37%

3–7 days

0 0.0%

1–4 weeks

6 32%

Over a month

0 0.0%

How the animals did

Recovered

7 15%

Recovered with lasting effects

4 8.5%

Still unwell when reported

5 11%

Died

3 6.4%

Euthanised

2 4.3%

Not known

26 55%

Problems reported at the same time

17 36%

13 28%

7 15%

6 13%

6 13%

6 13%

6 13%

6 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 eye or vision problems in dogs?: 47 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).

Eye or vision problems with similar medicines

Eye or vision problems after Pyrantel + Sarolaner (Simparica Trio) 152 reports · 0.3% of its reports
Eye or vision problems after Febantel + Praziquantel + Pyrantel (Drontal Plus) 21 reports · 0.3% of its reports
Eye or vision problems after Pyrantel 51 reports · 1.1% of its reports
Eye or vision problems after Praziquantel + Pyrantel 28 reports · 0.8% of its reports

All reported side effects of Fenbendazole in dogs · Medicines most reported with eye or vision problems