Mass after Fluralaner (Bravecto) in dogs

The FDA has received 37 reports of mass in dogs after Fluralaner. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

37Reports
76%Marked serious
19%Recovered
24%Died or euthanised
120 daysTypical onset
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How soon it started

Same day
0 0.0%
1–2 days
0 0.0%
3–7 days
0 0.0%
1–4 weeks
2 18%
Over a month
9 82%

How the animals did

Recovered
4 11%
Recovered with lasting effects
3 8.1%
Still unwell when reported
14 38%
Died
1 2.7%
Euthanised
8 22%
Not known
7 19%

Problems reported at the same time

Age of the animals

Under 1 year
1
1–3 years
2
4–7 years
6
8–11 years
14
12+ years
8

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 mass in dogs?
37 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 120 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).

Mass with similar medicines

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