Collapse after Afoxolaner (NexGard) in dogs

405 reports to the FDA describe collapse in dogs given Afoxolaner. That is 0.7% of all reports for this medicine, compared with 0.9% across reports for all dog medicines.

405Reports
73%Marked serious
38%Recovered
22%Died or euthanised
3 daysTypical onset
SponsoredWorried about your pet? Ask a veterinarian online, 24/7

How soon it started

Same day
91 27%
1–2 days
69 21%
3–7 days
51 15%
1–4 weeks
59 18%
Over a month
65 19%

How the animals did

Recovered
154 38%
Still unwell when reported
48 12%
Died
58 14%
Euthanised
33 8.1%
Not known
112 28%

Problems reported at the same time

Age of the animals

Under 1 year
52
1–3 years
103
4–7 years
88
8–11 years
85
12+ years
72

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 collapse in dogs?
405 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).

Collapse with similar medicines

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