Vomiting after Afoxolaner (NexGard) in dogs

The FDA has received 15,643 reports of vomiting in dogs after Afoxolaner. That is 27% of all reports for this medicine, compared with 28% across reports for all dog medicines.

15,643Reports

40%Marked serious

58%Recovered

2.8%Died or euthanised

Same dayTypical onset

How soon it started

Same day

7,062 53%

1–2 days

1,969 15%

3–7 days

592 4.5%

1–4 weeks

919 6.9%

Over a month

2,697 20%

How the animals did

Recovered

9,099 58%

Recovered with lasting effects

17 0.1%

Still unwell when reported

654 4.2%

Died

238 1.5%

Euthanised

199 1.3%

Not known

5,436 35%

Problems reported at the same time

3,144 20%

2,668 17%

2,102 13%

688 4.4%

537 3.4%

525 3.4%

452 2.9%

428 2.7%

Age of the animals

Under 1 year

3,560

1–3 years

4,124

4–7 years

3,292

8–11 years

2,169

12+ years

925

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 vomiting in dogs?: 15,643 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 the same day 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).

Vomiting with similar medicines

Vomiting after Fluralaner (Bravecto) 26,091 reports · 38% of its reports
Vomiting after Sarolaner (Simparica) 4,059 reports · 24% of its reports
Vomiting after Lotilaner (Credelio) 3,043 reports · 31% of its reports
Vomiting after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 1,792 reports · 19% of its reports
Vomiting after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 1,058 reports · 34% of its reports

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