Hypothermia after Selamectin (Revolution) in cats

The FDA has received 181 reports of hypothermia in cats after Selamectin. That is 0.8% of all reports for this medicine, compared with 1.2% across reports for all cat medicines.

181Reports
30%Marked serious
2.8%Recovered
56%Died or euthanised
1 daysTypical onset
SponsoredWorried about your pet? Ask a veterinarian online, 24/7

How soon it started

Same day
22 33%
1–2 days
28 42%
3–7 days
10 15%
1–4 weeks
3 4.5%
Over a month
3 4.5%

How the animals did

Recovered
5 2.8%
Still unwell when reported
28 15%
Died
85 47%
Euthanised
16 8.8%
Not known
47 26%

Problems reported at the same time

Age of the animals

Under 1 year
92
1–3 years
26
4–7 years
23
8–11 years
17
12+ years
22

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 hypothermia in cats?
181 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).

Hypothermia with similar medicines

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