Didn't work as expected after Fluralaner (Bravecto) in dogs

The FDA has received 5,946 reports of didn't work as expected in dogs after Fluralaner. That is 8.6% of all reports for this medicine, compared with 13% across reports for all dog medicines.

5,946Reports

58%Marked serious

9.2%Recovered

1.1%Died or euthanised

57 daysTypical onset

How soon it started

Same day

409 19%

1–2 days

52 2.4%

3–7 days

78 3.5%

1–4 weeks

309 14%

Over a month

1,352 61%

How the animals did

Recovered

522 8.8%

Recovered with lasting effects

26 0.4%

Still unwell when reported

4,412 74%

Died

32 0.5%

Euthanised

34 0.6%

Not known

920 15%

Problems reported at the same time

2,293 39%

414 7.0%

144 2.4%

98 1.6%

86 1.4%

82 1.4%

80 1.3%

Drug administration error

72 1.2%

Age of the animals

Under 1 year

270

1–3 years

1,998

4–7 years

1,857

8–11 years

1,171

12+ years

358

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 didn't work as expected in dogs?: 5,946 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 57 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 work as expected with similar medicines

Didn't work as expected after Afoxolaner (NexGard) 8,625 reports · 15% of its reports
Didn't work as expected after Sarolaner (Simparica) 1,487 reports · 8.9% of its reports
Didn't work as expected after Lotilaner (Credelio) 1,497 reports · 15% of its reports
Didn't work as expected after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 1,527 reports · 16% of its reports
Didn't work as expected after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 292 reports · 9.5% of its reports

All reported side effects of Fluralaner in dogs · Medicines most reported with didn't work as expected