Tense abdomen after Afoxolaner (NexGard) in dogs

The FDA has received 76 reports of tense abdomen in dogs after Afoxolaner. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines.

76Reports

61%Marked serious

28%Recovered

17%Died or euthanised

1 daysTypical onset

How soon it started

Same day

18 29%

1–2 days

20 32%

3–7 days

3 4.8%

1–4 weeks

7 11%

Over a month

14 23%

How the animals did

Recovered

21 28%

Still unwell when reported

8 11%

Died

5 6.6%

Euthanised

8 11%

Not known

34 45%

Problems reported at the same time

41 54%

33 43%

29 38%

25 33%

13 17%

13 17%

12 16%

11 14%

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.

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 tense abdomen in dogs?: 76 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 1 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).

Tense abdomen with similar medicines

Tense abdomen after Fluralaner (Bravecto) 119 reports · 0.2% of its reports

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