Pale mucous membrane after Selamectin (Revolution) in cats

103 reports to the FDA describe pale mucous membrane in cats given Selamectin. That is 0.5% of all reports for this medicine, compared with 0.6% across reports for all cat medicines.

103Reports
40%Marked serious
3.9%Recovered
37%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
17 33%
1–2 days
12 23%
3–7 days
8 15%
1–4 weeks
10 19%
Over a month
5 9.6%

How the animals did

Recovered
4 3.9%
Still unwell when reported
25 24%
Died
27 26%
Euthanised
11 11%
Not known
36 35%

Problems reported at the same time

Age of the animals

Under 1 year
29
1–3 years
25
4–7 years
17
8–11 years
17
12+ years
13

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 pale mucous membrane in cats?
103 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 2 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).

Pale mucous membrane with similar medicines

All reported side effects of Selamectin in cats · Medicines most reported with pale mucous membrane