Seizures after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) in dogs

500 reports to the FDA describe seizures in dogs given Afoxolaner + Moxidectin + Pyrantel. That is 5.4% of all reports for this medicine, compared with 4.4% across reports for all dog medicines.

500Reports

62%Marked serious

52%Recovered

7.4%Died or euthanised

2 daysTypical onset

How soon it started

Same day

107 23%

1–2 days

133 29%

3–7 days

73 16%

1–4 weeks

114 25%

Over a month

36 7.8%

How the animals did

Recovered

258 52%

Still unwell when reported

62 12%

Died

23 4.6%

Euthanised

14 2.8%

Not known

143 29%

Problems reported at the same time

89 18%

56 11%

55 11%

48 9.6%

46 9.2%

37 7.4%

34 6.8%

27 5.4%

Age of the animals

Under 1 year

1–3 years

161

4–7 years

153

8–11 years

12+ years

About this medicine

Afoxolaner kills fleas and ticks; given as a monthly chewable. Moxidectin prevents heartworm disease (monthly topical, or a 6- or 12-month injection for dogs). Pyrantel treats roundworms and hookworms.

Products with this combination include NexGard PLUS. 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 + Moxidectin + Pyrantel cause seizures in dogs?: 500 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).

Seizures with similar medicines

Seizures after Fluralaner (Bravecto) 3,501 reports · 5.1% of its reports
Seizures after Afoxolaner (NexGard) 4,287 reports · 7.5% of its reports
Seizures after Sarolaner (Simparica) 2,972 reports · 18% of its reports
Seizures after Lotilaner (Credelio) 686 reports · 6.9% of its reports
Seizures after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 141 reports · 4.6% of its reports

All reported side effects of Afoxolaner + Moxidectin + Pyrantel in dogs · Medicines most reported with seizures