Tremors after Sarolaner + Selamectin (Revolution Plus) in cats

269 reports to the FDA describe tremors in cats given Sarolaner + Selamectin. That is 3.3% of all reports for this medicine, compared with 2.6% across reports for all cat medicines.

269Reports
55%Marked serious
28%Recovered
4.1%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
136 52%
1–2 days
85 32%
3–7 days
22 8.4%
1–4 weeks
13 4.9%
Over a month
7 2.7%

How the animals did

Recovered
74 28%
Still unwell when reported
130 48%
Died
4 1.5%
Euthanised
7 2.6%
Not known
54 20%

Problems reported at the same time

Age of the animals

Under 1 year
58
1–3 years
75
4–7 years
45
8–11 years
33
12+ years
43

About this medicine

Sarolaner kills fleas, ticks and some mites; monthly. Selamectin prevents heartworm and treats fleas, ear mites and some worms (spot-on).

Products with this combination include Revolution Plus. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

In 2018 the FDA alerted owners and vets that isoxazoline products have been associated with neurologic reactions such as muscle tremors, wobbliness (ataxia) and seizures, including in animals with no history of them.

Questions owners ask

Can Sarolaner + Selamectin cause tremors in cats?
269 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 the same 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).

Tremors with similar medicines

All reported side effects of Sarolaner + Selamectin in cats · Medicines most reported with tremors