Abnormal cytology after Fluralaner (Bravecto) in dogs

The FDA has received 154 reports of abnormal cytology in dogs after Fluralaner. That is 0.2% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

154Reports
87%Marked serious
11%Recovered
22%Died or euthanised
14 daysTypical onset
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How soon it started

Same day
16 17%
1–2 days
12 13%
3–7 days
12 13%
1–4 weeks
17 18%
Over a month
35 38%

How the animals did

Recovered
11 7.1%
Recovered with lasting effects
6 3.9%
Still unwell when reported
73 47%
Died
13 8.4%
Euthanised
21 14%
Not known
30 19%

Problems reported at the same time

Age of the animals

Under 1 year
11
1–3 years
32
4–7 years
33
8–11 years
61
12+ years
13

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 abnormal cytology in dogs?
154 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 14 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).

Abnormal cytology with similar medicines

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