Didn't stop worms after Sarolaner (Simparica) in dogs

388 reports to the FDA describe didn't stop worms in dogs given Sarolaner. That is 2.3% of all reports for this medicine, compared with 8.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

388Reports

30%Marked serious

1.8%Recovered

0.0%Died or euthanised

104 daysTypical onset

How soon it started

Same day

17 8.4%

1–2 days

1 0.5%

3–7 days

3 1.5%

1–4 weeks

27 13%

Over a month

155 76%

How the animals did

Recovered

6 1.5%

Recovered with lasting effects

1 0.3%

Still unwell when reported

141 36%

Not known

240 62%

Problems reported at the same time

Intentional misuse

28 7.2%

Diarrhea

25 6.4%

Medication error

21 5.4%

Didn't work as expected

20 5.2%

18 4.6%

11 2.8%

7 1.8%

7 1.8%

Age of the animals

Under 1 year

1–3 years

158

4–7 years

8–11 years

12+ years

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 didn't stop worms in dogs?: 388 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 104 days 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).

Didn't stop worms with similar medicines

Didn't stop worms after Fluralaner (Bravecto) 629 reports · 0.9% of its reports
Didn't stop worms after Afoxolaner (NexGard) 1,124 reports · 2.0% of its reports
Didn't stop worms after Lotilaner (Credelio) 552 reports · 5.5% of its reports
Didn't stop worms after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 2,103 reports · 23% of its reports
Didn't stop worms after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 335 reports · 11% of its reports

All reported side effects of Sarolaner in dogs · Medicines most reported with didn't stop worms