Lymphopenia after Fluralaner (Bravecto) in dogs

198 reports to the FDA describe lymphopenia in dogs given Fluralaner. That is 0.3% of all reports for this medicine, compared with 0.3% across reports for all dog medicines.

198Reports
92%Marked serious
9.1%Recovered
32%Died or euthanised
5 daysTypical onset
SponsoredWorried about your pet? Ask a veterinarian online, 24/7

How soon it started

Same day
29 24%
1–2 days
25 21%
3–7 days
16 13%
1–4 weeks
18 15%
Over a month
32 27%

How the animals did

Recovered
14 7.1%
Recovered with lasting effects
4 2.0%
Still unwell when reported
86 43%
Died
16 8.1%
Euthanised
47 24%
Not known
31 16%

Problems reported at the same time

Age of the animals

Under 1 year
5
1–3 years
33
4–7 years
69
8–11 years
64
12+ years
27

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 lymphopenia in dogs?
198 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 5 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).

Lymphopenia with similar medicines

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