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

255 reports to the FDA describe didn't work as expected in cats given Fluralaner. That is 2.4% of all reports for this medicine, compared with 8.7% across reports for all cat medicines, so it is reported less often than average with this medicine.

255Reports
64%Marked serious
2.0%Recovered
25%Died or euthanised
41 daysTypical onset
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How soon it started

Same day
30 18%
1–2 days
2 1.2%
3–7 days
6 3.6%
1–4 weeks
27 16%
Over a month
101 61%

How the animals did

Recovered
5 2.0%
Still unwell when reported
163 64%
Died
37 15%
Euthanised
28 11%
Not known
22 8.6%

Problems reported at the same time

Age of the animals

Under 1 year
28
1–3 years
87
4–7 years
43
8–11 years
39
12+ years
25

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 cats?
255 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 41 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

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