Musculoskeletal disorder after Afoxolaner (NexGard) in dogs

225 reports to the FDA describe musculoskeletal disorder in dogs given Afoxolaner. That is 0.4% of all reports for this medicine, compared with 0.3% across reports for all dog medicines.

225Reports
80%Marked serious
23%Recovered
14%Died or euthanised
4 daysTypical onset
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How soon it started

Same day
42 26%
1–2 days
32 20%
3–7 days
16 9.9%
1–4 weeks
19 12%
Over a month
52 32%

How the animals did

Recovered
50 22%
Recovered with lasting effects
1 0.4%
Still unwell when reported
28 12%
Died
18 8.0%
Euthanised
14 6.2%
Not known
114 51%

Problems reported at the same time

Age of the animals

Under 1 year
14
1–3 years
38
4–7 years
72
8–11 years
48
12+ years
40

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 musculoskeletal disorder in dogs?
225 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 4 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).

Musculoskeletal disorder with similar medicines

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