Liver problems after Selamectin (Revolution) in cats

The FDA has received 386 reports of liver problems in cats after Selamectin. That is 1.8% of all reports for this medicine, compared with 2.8% across reports for all cat medicines, so it is reported less often than average with this medicine.

386Reports
23%Marked serious
5.2%Recovered
27%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
37 26%
1–2 days
41 29%
3–7 days
18 13%
1–4 weeks
19 13%
Over a month
26 18%

How the animals did

Recovered
19 4.9%
Recovered with lasting effects
1 0.3%
Still unwell when reported
78 20%
Died
79 20%
Euthanised
24 6.2%
Not known
185 48%

Problems reported at the same time

Age of the animals

Under 1 year
76
1–3 years
78
4–7 years
84
8–11 years
81
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 liver problems in cats?
386 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).

Liver problems with similar medicines

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