Didn't stop ticks after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) in dogs

The FDA has received 273 reports of didn't stop ticks in dogs after Afoxolaner + Moxidectin + Pyrantel. That is 2.9% of all reports for this medicine, compared with 2.3% across reports for all dog medicines.

273Reports

2.9%Marked serious

35%Recovered

0.4%Died or euthanised

14 daysTypical onset

How soon it started

Same day

5 2.1%

1–2 days

38 16%

3–7 days

41 17%

1–4 weeks

102 43%

Over a month

51 22%

How the animals did

Recovered

96 35%

Still unwell when reported

36 13%

Euthanised

1 0.4%

Not known

140 51%

Problems reported at the same time

Didn't work as expected

76 28%

17 6.2%

9 3.3%

5 1.8%

4 1.5%

2 0.7%

2 0.7%

2 0.7%

Age of the animals

Under 1 year

1–3 years

4–7 years

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 didn't stop ticks in dogs?: 273 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 14 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).

Didn't stop ticks with similar medicines

Didn't stop ticks after Fluralaner (Bravecto) 6,711 reports · 9.8% of its reports
Didn't stop ticks after Afoxolaner (NexGard) 8,328 reports · 15% of its reports
Didn't stop ticks after Sarolaner (Simparica) 2,073 reports · 12% of its reports
Didn't stop ticks after Lotilaner (Credelio) 843 reports · 8.5% of its reports
Didn't stop ticks after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 53 reports · 1.7% of its reports

All reported side effects of Afoxolaner + Moxidectin + Pyrantel in dogs · Medicines most reported with didn't stop ticks