Hypoproteinaemia after Fenbendazole in dogs

The FDA has received 32 reports of hypoproteinaemia in dogs after Fenbendazole. That is 0.5% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

32Reports

75%Marked serious

6.3%Recovered

34%Died or euthanised

13 daysTypical onset

How soon it started

Same day

2 8.3%

1–2 days

5 21%

3–7 days

2 8.3%

1–4 weeks

8 33%

Over a month

7 29%

How the animals did

Recovered

2 6.3%

Still unwell when reported

10 31%

Died

4 13%

Euthanised

7 22%

Not known

9 28%

Problems reported at the same time

18 56%

17 53%

15 47%

12 38%

11 34%

11 34%

10 31%

9 28%

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 hypoproteinaemia in dogs?: 32 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 13 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).

Hypoproteinaemia with similar medicines

Hypoproteinaemia after Pyrantel + Sarolaner (Simparica Trio) 38 reports · 0.1% of its reports
Hypoproteinaemia after Pyrantel 22 reports · 0.5% of its reports

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