Excessive urination after Afoxolaner (NexGard) in dogs

205 reports to the FDA describe excessive urination in dogs given Afoxolaner. That is 0.4% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported less often than average with this medicine.

205Reports
53%Marked serious
15%Recovered
11%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
52 31%
1–2 days
40 24%
3–7 days
20 12%
1–4 weeks
19 11%
Over a month
36 22%

How the animals did

Recovered
30 15%
Recovered with lasting effects
1 0.5%
Still unwell when reported
48 23%
Died
10 4.9%
Euthanised
13 6.3%
Not known
103 50%

Problems reported at the same time

Age of the animals

Under 1 year
26
1–3 years
27
4–7 years
47
8–11 years
60
12+ years
37

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 urination in dogs?
205 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 2 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).

Excessive urination with similar medicines

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