Fever after Fluralaner (Bravecto) in cats

The FDA has received 194 reports of fever in cats after Fluralaner. That is 1.8% of all reports for this medicine, compared with 3.2% across reports for all cat medicines, so it is reported less often than average with this medicine.

194Reports
95%Marked serious
24%Recovered
11%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
69 41%
1–2 days
49 29%
3–7 days
17 10%
1–4 weeks
24 14%
Over a month
11 6.5%

How the animals did

Recovered
44 23%
Recovered with lasting effects
2 1.0%
Still unwell when reported
99 51%
Died
10 5.2%
Euthanised
11 5.7%
Not known
28 14%

Problems reported at the same time

Age of the animals

Under 1 year
20
1–3 years
77
4–7 years
40
8–11 years
25
12+ years
31

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 fever in cats?
194 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).

Fever with similar medicines

All reported side effects of Fluralaner in cats · Medicines most reported with fever