Excessive thirst after Afoxolaner (NexGard) in dogs

422 reports to the FDA describe excessive thirst in dogs given Afoxolaner. That is 0.7% of all reports for this medicine, compared with 1.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

422Reports

55%Marked serious

26%Recovered

11%Died or euthanised

1 daysTypical onset

How soon it started

Same day

134 39%

1–2 days

75 22%

3–7 days

35 10%

1–4 weeks

32 9.2%

Over a month

70 20%

How the animals did

Recovered

109 26%

Recovered with lasting effects

1 0.2%

Still unwell when reported

61 14%

Died

23 5.5%

Euthanised

25 5.9%

Not known

203 48%

Problems reported at the same time

143 34%

140 33%

122 29%

117 28%

85 20%

74 18%

64 15%

64 15%

Age of the animals

Under 1 year

1–3 years

4–7 years

110

8–11 years

119

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 excessive thirst in dogs?: 422 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).

Excessive thirst with similar medicines

Excessive thirst after Fluralaner (Bravecto) 634 reports · 0.9% of its reports
Excessive thirst after Sarolaner (Simparica) 93 reports · 0.6% of its reports
Excessive thirst after Lotilaner (Credelio) 106 reports · 1.1% of its reports
Excessive thirst after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 30 reports · 0.3% of its reports
Excessive thirst after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 22 reports · 0.7% of its reports

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