Dilated pupils after Fluralaner + Moxidectin (Bravecto Plus) in cats

The FDA has received 51 reports of dilated pupils in cats after Fluralaner + Moxidectin. That is 1.6% of all reports for this medicine, compared with 1.4% across reports for all cat medicines.

51Reports
63%Marked serious
33%Recovered
0.0%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
16 48%
1–2 days
8 24%
3–7 days
2 6.1%
1–4 weeks
4 12%
Over a month
3 9.1%

How the animals did

Recovered
16 31%
Recovered with lasting effects
1 2.0%
Still unwell when reported
27 53%
Not known
7 14%

Problems reported at the same time

Age of the animals

Under 1 year
7
1–3 years
19
4–7 years
14
8–11 years
3
12+ years
7

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 dilated pupils in cats?
51 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 1 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).

Dilated pupils with similar medicines

All reported side effects of Fluralaner + Moxidectin in cats · Medicines most reported with dilated pupils