Monocytosis after Fluralaner (Bravecto) in dogs

258 reports to the FDA describe monocytosis in dogs given Fluralaner. That is 0.4% of all reports for this medicine, compared with 0.3% across reports for all dog medicines.

258Reports
95%Marked serious
5.0%Recovered
34%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
40 24%
1–2 days
54 32%
3–7 days
13 7.7%
1–4 weeks
22 13%
Over a month
40 24%

How the animals did

Recovered
11 4.3%
Recovered with lasting effects
2 0.8%
Still unwell when reported
129 50%
Died
31 12%
Euthanised
58 22%
Not known
27 10%

Problems reported at the same time

Age of the animals

Under 1 year
25
1–3 years
56
4–7 years
70
8–11 years
71
12+ years
36

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 monocytosis in dogs?
258 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).

Monocytosis with similar medicines

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