Bradycardia after Selamectin (Revolution) in dogs

32 reports to the FDA describe bradycardia in dogs given Selamectin. That is 0.1% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

32Reports
31%Marked serious
16%Recovered
19%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
5 36%
1–2 days
2 14%
3–7 days
4 29%
1–4 weeks
0 0.0%
Over a month
3 21%

How the animals did

Recovered
5 16%
Still unwell when reported
5 16%
Died
5 16%
Euthanised
1 3.1%
Not known
16 50%

Problems reported at the same time

Age of the animals

Under 1 year
10
1–3 years
12
4–7 years
5
8–11 years
3
12+ years
2

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 bradycardia in dogs?
32 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 3 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).

Bradycardia with similar medicines

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