Unresponsive after Afoxolaner (NexGard) in dogs

The FDA has received 223 reports of unresponsive in dogs after Afoxolaner. That is 0.4% of all reports for this medicine, compared with 0.4% across reports for all dog medicines.

223Reports
80%Marked serious
32%Recovered
29%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
50 27%
1–2 days
41 22%
3–7 days
23 13%
1–4 weeks
24 13%
Over a month
46 25%

How the animals did

Recovered
71 32%
Still unwell when reported
18 8.1%
Died
31 14%
Euthanised
33 15%
Not known
70 31%

Problems reported at the same time

Age of the animals

Under 1 year
34
1–3 years
48
4–7 years
55
8–11 years
58
12+ years
23

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 unresponsive in dogs?
223 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).

Unresponsive with similar medicines

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