Leucocytosis after Selamectin (Revolution) in dogs

The FDA has received 172 reports of leucocytosis in dogs after Selamectin. That is 0.6% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported less often than average with this medicine.

172Reports

17%Marked serious

3.5%Recovered

26%Died or euthanised

2 daysTypical onset

How soon it started

Same day

15 35%

1–2 days

8 19%

3–7 days

4 9.3%

1–4 weeks

8 19%

Over a month

8 19%

How the animals did

Recovered

6 3.5%

Still unwell when reported

27 16%

Died

37 22%

Euthanised

8 4.7%

Not known

94 55%

Problems reported at the same time

82 48%

66 38%

64 37%

61 35%

52 30%

47 27%

47 27%

38 22%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Selamectin prevents heartworm and treats fleas, ear mites and some worms (spot-on).

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

Some herding breeds (for example Collies) carry the MDR1 gene variant and can be more sensitive to this drug class at high doses.

Questions owners ask

Can Selamectin cause leucocytosis in dogs?: 172 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 2 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).

Leucocytosis with similar medicines

Leucocytosis after Ivermectin + Pyrantel (Heartgard Plus) 401 reports · 0.3% of its reports
Leucocytosis after Milbemycin Oxime + Spinosad (Trifexis) 474 reports · 0.4% of its reports
Leucocytosis after Moxidectin (ProHeart 6) 773 reports · 1.5% of its reports
Leucocytosis after Milbemycin Oxime + Praziquantel (Interceptor Plus) 136 reports · 0.4% of its reports
Leucocytosis after Milbemycin Oxime (Interceptor) 134 reports · 0.5% of its reports
Leucocytosis after Ivermectin (Heartgard) 109 reports · 0.9% of its reports
Leucocytosis after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 22 reports · 0.3% of its reports

All reported side effects of Selamectin in dogs · Medicines most reported with leucocytosis