Death after Afoxolaner (NexGard) in dogs

1,829 reports to the FDA describe death in dogs given Afoxolaner. That is 3.2% of all reports for this medicine, compared with 5.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

1,829Reports
98%Marked serious
0.2%Recovered
99%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
342 25%
1–2 days
322 23%
3–7 days
161 12%
1–4 weeks
251 18%
Over a month
315 23%

How the animals did

Recovered
4 0.2%
Died
1,077 59%
Euthanised
740 40%
Not known
8 0.4%

Problems reported at the same time

Age of the animals

Under 1 year
172
1–3 years
180
4–7 years
332
8–11 years
437
12+ years
440

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 death in dogs?
1,829 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).

Death with similar medicines

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