Behaviour change after Fluralaner (Bravecto) in dogs

The FDA has received 1,712 reports of behaviour change in dogs after Fluralaner. That is 2.5% of all reports for this medicine, compared with 2.5% across reports for all dog medicines.

1,712Reports

74%Marked serious

32%Recovered

9.5%Died or euthanised

1 daysTypical onset

How soon it started

Same day

373 35%

1–2 days

245 23%

3–7 days

126 12%

1–4 weeks

113 11%

Over a month

205 19%

How the animals did

Recovered

518 30%

Recovered with lasting effects

38 2.2%

Still unwell when reported

728 43%

Died

54 3.2%

Euthanised

109 6.4%

Not known

265 15%

Problems reported at the same time

536 31%

402 23%

379 22%

375 22%

352 21%

241 14%

208 12%

197 12%

Age of the animals

Under 1 year

133

1–3 years

481

4–7 years

511

8–11 years

393

12+ years

155

About this medicine

Fluralaner kills fleas and ticks for up to 12 weeks (chewable or spot-on).

Products with this ingredient include Bravecto. 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 Fluralaner cause behaviour change in dogs?: 1,712 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).

Behaviour change with similar medicines

Behaviour change after Afoxolaner (NexGard) 1,819 reports · 3.2% of its reports
Behaviour change after Sarolaner (Simparica) 718 reports · 4.3% of its reports
Behaviour change after Lotilaner (Credelio) 488 reports · 4.9% of its reports
Behaviour change after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 172 reports · 1.9% of its reports
Behaviour change after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 199 reports · 6.5% of its reports

All reported side effects of Fluralaner in dogs · Medicines most reported with behaviour change