Constipation after Fenbendazole in dogs

44 reports to the FDA describe constipation in dogs given Fenbendazole. That is 0.7% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

44Reports

20%Marked serious

6.8%Recovered

6.8%Died or euthanised

1 daysTypical onset

How soon it started

Same day

9 50%

1–2 days

5 28%

3–7 days

1 5.6%

1–4 weeks

1 5.6%

Over a month

2 11%

How the animals did

Recovered

3 6.8%

Still unwell when reported

12 27%

Died

2 4.5%

Euthanised

1 2.3%

Not known

26 59%

Problems reported at the same time

10 23%

10 23%

6 14%

5 11%

4 9.1%

4 9.1%

3 6.8%

3 6.8%

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 constipation in dogs?: 44 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).

Constipation with similar medicines

Constipation after Pyrantel + Sarolaner (Simparica Trio) 42 reports · 0.1% of its reports
Constipation after Febantel + Praziquantel + Pyrantel (Drontal Plus) 28 reports · 0.4% of its reports
Constipation after Pyrantel 24 reports · 0.5% of its reports
Constipation after Praziquantel + Pyrantel 41 reports · 1.1% of its reports

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