Head down after Afoxolaner (NexGard) in dogs

The FDA has received 62 reports of head down in dogs after Afoxolaner. That is 0.1% of all reports for this medicine, compared with 0.0% across reports for all dog medicines, so it is reported unusually often with this medicine.

62Reports
47%Marked serious
31%Recovered
13%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
13 26%
1–2 days
14 28%
3–7 days
6 12%
1–4 weeks
7 14%
Over a month
10 20%

How the animals did

Recovered
19 31%
Still unwell when reported
6 9.7%
Died
4 6.5%
Euthanised
4 6.5%
Not known
29 47%

Problems reported at the same time

Age of the animals

Under 1 year
7
1–3 years
15
4–7 years
11
8–11 years
19
12+ years
10

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 head down in dogs?
62 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 2 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).

Head down with similar medicines

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