Not drinking after Selamectin (Revolution) in cats

The FDA has received 104 reports of not drinking in cats after Selamectin. That is 0.5% of all reports for this medicine, compared with 1.1% across reports for all cat medicines, so it is reported less often than average with this medicine.

104Reports
43%Marked serious
18%Recovered
14%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
47 48%
1–2 days
29 30%
3–7 days
5 5.1%
1–4 weeks
7 7.1%
Over a month
10 10%

How the animals did

Recovered
16 15%
Recovered with lasting effects
3 2.9%
Still unwell when reported
45 43%
Died
5 4.8%
Euthanised
10 9.6%
Not known
25 24%

Problems reported at the same time

Age of the animals

Under 1 year
20
1–3 years
27
4–7 years
18
8–11 years
19
12+ years
15

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 not drinking in cats?
104 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).

Not drinking with similar medicines

All reported side effects of Selamectin in cats · Medicines most reported with not drinking