Excessive thirst after Fenbendazole in dogs

The FDA has received 65 reports of excessive thirst in dogs after Fenbendazole. That is 1.1% of all reports for this medicine, compared with 1.4% across reports for all dog medicines.

65Reports

37%Marked serious

20%Recovered

20%Died or euthanised

1 daysTypical onset

How soon it started

Same day

11 44%

1–2 days

6 24%

3–7 days

3 12%

1–4 weeks

3 12%

Over a month

2 8.0%

How the animals did

Recovered

13 20%

Still unwell when reported

10 15%

Died

8 12%

Euthanised

5 7.7%

Not known

29 45%

Problems reported at the same time

25 38%

21 32%

20 31%

18 28%

18 28%

12 18%

8 12%

Restlessness or agitation

8 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 excessive thirst in dogs?: 65 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).

Excessive thirst with similar medicines

Excessive thirst after Pyrantel + Sarolaner (Simparica Trio) 332 reports · 0.6% of its reports
Excessive thirst after Febantel + Praziquantel + Pyrantel (Drontal Plus) 62 reports · 0.9% of its reports
Excessive thirst after Pyrantel 42 reports · 0.9% of its reports
Excessive thirst after Praziquantel + Pyrantel 27 reports · 0.7% of its reports

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