Dehydration after Selamectin (Revolution) in cats

299 reports to the FDA describe dehydration in cats given Selamectin. That is 1.4% of all reports for this medicine, compared with 2.0% across reports for all cat medicines.

299Reports

25%Marked serious

8.7%Recovered

31%Died or euthanised

1 daysTypical onset

How soon it started

Same day

43 36%

1–2 days

36 30%

3–7 days

18 15%

1–4 weeks

11 9.2%

Over a month

11 9.2%

How the animals did

Recovered

24 8.0%

Recovered with lasting effects

2 0.7%

Still unwell when reported

55 18%

Died

73 24%

Euthanised

20 6.7%

Not known

125 42%

Problems reported at the same time

209 70%

197 66%

134 45%

90 30%

88 29%

65 22%

58 19%

52 17%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 dehydration in cats?: 299 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).

Dehydration with similar medicines

Dehydration after Eprinomectin + Esafoxolaner + Praziquantel (NexGard Combo) 60 reports · 1.8% of its reports

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