Lethargy after Pimobendan (Vetmedin) in dogs

The FDA has received 818 reports of lethargy in dogs after Pimobendan. That is 14% of all reports for this medicine, compared with 11% across reports for all dog medicines.

818Reports

41%Marked serious

26%Recovered

17%Died or euthanised

7 daysTypical onset

How soon it started

Same day

122 23%

1–2 days

90 17%

3–7 days

68 13%

1–4 weeks

80 15%

Over a month

170 32%

How the animals did

Recovered

201 25%

Recovered with lasting effects

8 1.0%

Still unwell when reported

111 14%

Died

71 8.7%

Euthanised

71 8.7%

Not known

356 44%

Problems reported at the same time

330 40%

211 26%

167 20%

142 17%

121 15%

86 11%

66 8.1%

60 7.3%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

271

12+ years

424

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 lethargy in dogs?: 818 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 7 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 lethargy