Weight loss after Fluralaner (Bravecto) in cats

207 reports to the FDA describe weight loss in cats given Fluralaner. That is 1.9% of all reports for this medicine, compared with 4.6% across reports for all cat medicines, so it is reported less often than average with this medicine.

207Reports
88%Marked serious
14%Recovered
20%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
53 34%
1–2 days
36 23%
3–7 days
14 9.1%
1–4 weeks
25 16%
Over a month
26 17%

How the animals did

Recovered
15 7.2%
Recovered with lasting effects
13 6.3%
Still unwell when reported
105 51%
Died
12 5.8%
Euthanised
29 14%
Not known
33 16%

Problems reported at the same time

Age of the animals

Under 1 year
10
1–3 years
32
4–7 years
47
8–11 years
50
12+ years
64

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 weight loss in cats?
207 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 2 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).

Weight loss with similar medicines

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