Tremors after Sarolaner (Simparica) in dogs

The FDA has received 2,370 reports of tremors in dogs after Sarolaner. That is 14% of all reports for this medicine, compared with 3.4% across reports for all dog medicines, so it is reported unusually often with this medicine.

2,370Reports

41%Marked serious

27%Recovered

2.4%Died or euthanised

Same dayTypical onset

How soon it started

Same day

1,329 60%

1–2 days

466 21%

3–7 days

152 6.8%

1–4 weeks

111 5.0%

Over a month

165 7.4%

How the animals did

Recovered

639 27%

Recovered with lasting effects

1 0.0%

Still unwell when reported

1,156 49%

Died

22 0.9%

Euthanised

36 1.5%

Not known

516 22%

Problems reported at the same time

580 24%

448 19%

370 16%

310 13%

272 11%

194 8.2%

166 7.0%

136 5.7%

Age of the animals

Under 1 year

122

1–3 years

500

4–7 years

480

8–11 years

616

12+ years

551

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 tremors in dogs?: 2,370 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

Tremors after Fluralaner (Bravecto) 2,377 reports · 3.5% of its reports
Tremors after Afoxolaner (NexGard) 2,689 reports · 4.7% of its reports
Tremors after Lotilaner (Credelio) 496 reports · 5.0% of its reports
Tremors after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 347 reports · 3.7% of its reports
Tremors after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 129 reports · 4.2% of its reports

All reported side effects of Sarolaner in dogs · Medicines most reported with tremors