Loss of appetite after Selamectin (Revolution) in cats

The FDA has received 2,481 reports of loss of appetite in cats after Selamectin. That is 11% of all reports for this medicine, compared with 14% across reports for all cat medicines.

2,481Reports
16%Marked serious
9.1%Recovered
15%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
444 38%
1–2 days
388 34%
3–7 days
148 13%
1–4 weeks
104 9.0%
Over a month
72 6.2%

How the animals did

Recovered
222 8.9%
Recovered with lasting effects
5 0.2%
Still unwell when reported
531 21%
Died
291 12%
Euthanised
70 2.8%
Not known
1,362 55%

Problems reported at the same time

1,482 60%
779 31%
379 15%
354 14%
316 13%
211 8.5%

Age of the animals

Under 1 year
578
1–3 years
585
4–7 years
443
8–11 years
392
12+ years
347

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 loss of appetite in cats?
2,481 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).

Loss of appetite with similar medicines

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