Syncope after Pimobendan (Vetmedin) in dogs

108 reports to the FDA describe syncope in dogs given Pimobendan. That is 1.9% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

108Reports

62%Marked serious

10%Recovered

31%Died or euthanised

56 daysTypical onset

How soon it started

Same day

8 16%

1–2 days

1 2.0%

3–7 days

2 4.0%

1–4 weeks

10 20%

Over a month

29 58%

How the animals did

Recovered

10 9.3%

Recovered with lasting effects

1 0.9%

Still unwell when reported

7 6.5%

Died

18 17%

Euthanised

15 14%

Not known

57 53%

Problems reported at the same time

32 30%

26 24%

25 23%

20 19%

16 15%

15 14%

14 13%

8 7.4%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Pimobendan treats heart failure and some heart disease.

Products with this ingredient include Vetmedin. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Pimobendan cause syncope in dogs?: 108 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 56 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).

All reported side effects of Pimobendan in dogs · Medicines most reported with syncope