Falling after Selamectin (Revolution) in cats

The FDA has received 64 reports of falling in cats after Selamectin. That is 0.3% of all reports for this medicine, compared with 0.5% across reports for all cat medicines, so it is reported less often than average with this medicine.

64Reports
45%Marked serious
19%Recovered
16%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
28 46%
1–2 days
16 26%
3–7 days
5 8.2%
1–4 weeks
7 11%
Over a month
5 8.2%

How the animals did

Recovered
11 17%
Recovered with lasting effects
1 1.6%
Still unwell when reported
29 45%
Died
3 4.7%
Euthanised
7 11%
Not known
13 20%

Problems reported at the same time

Age of the animals

Under 1 year
15
1–3 years
10
4–7 years
16
8–11 years
7
12+ years
15

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 falling in cats?
64 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).

Falling with similar medicines

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