Seizures after Sarolaner (Simparica) in cats

The FDA has received 105 reports of seizures in cats after Sarolaner. That is 41% of all reports for this medicine, compared with 2.6% across reports for all cat medicines, so it is reported unusually often with this medicine.

105Reports
100%Marked serious
12%Recovered
4.8%Died or euthanised
Same dayTypical onset
SponsoredWorried about your pet? Ask a veterinarian online, 24/7

How soon it started

Same day
79 76%
1–2 days
21 20%
3–7 days
2 1.9%
1–4 weeks
1 1.0%
Over a month
1 1.0%

How the animals did

Recovered
13 12%
Still unwell when reported
81 77%
Died
2 1.9%
Euthanised
3 2.9%
Not known
6 5.7%

Problems reported at the same time

Age of the animals

Under 1 year
31
1–3 years
15
4–7 years
13
8–11 years
9
12+ years
24

About this medicine

Sarolaner kills fleas, ticks and some mites; monthly.

Products with this ingredient include Simparica. 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 cause seizures in cats?
105 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).

Seizures with similar medicines

All reported side effects of Sarolaner in cats · Medicines most reported with seizures