Stiffness after Afoxolaner (NexGard) in dogs

282 reports to the FDA describe stiffness in dogs given Afoxolaner. That is 0.5% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

282Reports
54%Marked serious
43%Recovered
8.9%Died or euthanised
3 daysTypical onset
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How soon it started

Same day
55 24%
1–2 days
45 19%
3–7 days
43 19%
1–4 weeks
49 21%
Over a month
40 17%

How the animals did

Recovered
122 43%
Still unwell when reported
23 8.2%
Died
15 5.3%
Euthanised
10 3.5%
Not known
112 40%

Problems reported at the same time

Age of the animals

Under 1 year
38
1–3 years
67
4–7 years
83
8–11 years
54
12+ years
38

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 stiffness in dogs?
282 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).

Stiffness with similar medicines

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