Foaming at the mouth after Fluralaner + Moxidectin (Bravecto Plus) in cats

173 reports to the FDA describe foaming at the mouth in cats given Fluralaner + Moxidectin. That is 5.3% of all reports for this medicine, compared with 1.3% across reports for all cat medicines, so it is reported unusually often with this medicine.

173Reports
29%Marked serious
53%Recovered
2.9%Died or euthanised
Same dayTypical onset
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How soon it started

Same day
143 97%
1–2 days
2 1.4%
3–7 days
0 0.0%
1–4 weeks
1 0.7%
Over a month
2 1.4%

How the animals did

Recovered
92 53%
Still unwell when reported
71 41%
Died
4 2.3%
Euthanised
1 0.6%
Not known
5 2.9%

Problems reported at the same time

Age of the animals

Under 1 year
29
1–3 years
63
4–7 years
42
8–11 years
24
12+ years
10

About this medicine

Fluralaner kills fleas and ticks for up to 12 weeks (chewable or spot-on). Moxidectin prevents heartworm disease (monthly topical, or a 6- or 12-month injection for dogs).

Products with this combination include Bravecto Plus. 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 + Moxidectin cause foaming at the mouth in cats?
173 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 the same 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).

Foaming at the mouth with similar medicines

All reported side effects of Fluralaner + Moxidectin in cats · Medicines most reported with foaming at the mouth