Malaise after Afoxolaner (NexGard) in dogs

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

150Reports
45%Marked serious
34%Recovered
10%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
34 31%
1–2 days
21 19%
3–7 days
7 6.3%
1–4 weeks
10 9.0%
Over a month
39 35%

How the animals did

Recovered
51 34%
Still unwell when reported
24 16%
Died
3 2.0%
Euthanised
12 8.0%
Not known
60 40%

Problems reported at the same time

Age of the animals

Under 1 year
27
1–3 years
23
4–7 years
35
8–11 years
32
12+ years
19

About this medicine

Afoxolaner kills fleas and ticks; given as a monthly chewable.

Products with this ingredient include NexGard. 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 Afoxolaner cause malaise in dogs?
150 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 3 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).

Malaise with similar medicines

All reported side effects of Afoxolaner in dogs · Medicines most reported with malaise