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

The FDA has received 372 reports of didn't stop fleas in dogs after Afoxolaner + Moxidectin + Pyrantel. That is 4.0% of all reports for this medicine, compared with 6.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

372Reports

0.8%Marked serious

5.1%Recovered

0.0%Died or euthanised

11 daysTypical onset

How soon it started

Same day

22 6.1%

1–2 days

69 19%

3–7 days

58 16%

1–4 weeks

166 46%

Over a month

46 13%

How the animals did

Recovered

19 5.1%

Still unwell when reported

20 5.4%

Not known

333 90%

Problems reported at the same time

17 4.6%

11 3.0%

8 2.2%

6 1.6%

4 1.1%

Skin rash or irritation

3 0.8%

Hair loss

3 0.8%

Tablets, abnormal

3 0.8%

Age of the animals

Under 1 year

1–3 years

122

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 fleas in dogs?: 372 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 11 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 fleas with similar medicines

Didn't stop fleas after Fluralaner (Bravecto) 16,499 reports · 24% of its reports
Didn't stop fleas after Afoxolaner (NexGard) 5,900 reports · 10% of its reports
Didn't stop fleas after Sarolaner (Simparica) 1,139 reports · 6.8% of its reports
Didn't stop fleas after Lotilaner (Credelio) 613 reports · 6.2% of its reports
Didn't stop fleas after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 84 reports · 2.7% of its reports

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