Polycythaemia after Melarsomine (Immiticide) in dogs

The FDA has received 47 reports of polycythaemia in dogs after Melarsomine. That is 0.2% 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.

47Reports

32%Marked serious

2.1%Recovered

6.4%Died or euthanised

7 daysTypical onset

How soon it started

Same day

3 25%

1–2 days

0 0.0%

3–7 days

5 42%

1–4 weeks

2 17%

Over a month

2 17%

How the animals did

Recovered

1 2.1%

Still unwell when reported

3 6.4%

Died

3 6.4%

Not known

40 85%

Problems reported at the same time

30 64%

24 51%

24 51%

17 36%

12 26%

11 23%

9 19%

9 19%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Melarsomine treats adult heartworm infection (a series of injections given by a vet).

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

Questions owners ask

Can Melarsomine cause polycythaemia in dogs?: 47 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 Melarsomine in dogs · Medicines most reported with polycythaemia