Neurological signs after Selamectin (Revolution) in cats

99 reports to the FDA describe neurological signs in cats given Selamectin. That is 0.5% of all reports for this medicine, compared with 0.5% across reports for all cat medicines.

99Reports
28%Marked serious
8.1%Recovered
25%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
23 49%
1–2 days
13 28%
3–7 days
4 8.5%
1–4 weeks
2 4.3%
Over a month
5 11%

How the animals did

Recovered
8 8.1%
Still unwell when reported
17 17%
Died
19 19%
Euthanised
6 6.1%
Not known
49 49%

Problems reported at the same time

Age of the animals

Under 1 year
38
1–3 years
18
4–7 years
17
8–11 years
9
12+ years
7

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 neurological signs in cats?
99 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 1 day 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).

Neurological signs with similar medicines

All reported side effects of Selamectin in cats · Medicines most reported with neurological signs