Vocalising after Selamectin (Revolution) in cats

The FDA has received 407 reports of vocalising in cats after Selamectin. That is 1.9% of all reports for this medicine, compared with 3.1% across reports for all cat medicines, so it is reported less often than average with this medicine.

407Reports
21%Marked serious
15%Recovered
20%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
120 56%
1–2 days
43 20%
3–7 days
13 6.0%
1–4 weeks
20 9.3%
Over a month
19 8.8%

How the animals did

Recovered
58 14%
Recovered with lasting effects
3 0.7%
Still unwell when reported
53 13%
Died
71 17%
Euthanised
9 2.2%
Not known
213 52%

Problems reported at the same time

Age of the animals

Under 1 year
77
1–3 years
106
4–7 years
85
8–11 years
54
12+ years
57

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 vocalising in cats?
407 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 the same 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).

Vocalising with similar medicines

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