Urinary tract infection after Afoxolaner (NexGard) in dogs

The FDA has received 150 reports of urinary tract infection in dogs after Afoxolaner. That is 0.3% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported less often than average with this medicine.

150Reports
45%Marked serious
23%Recovered
9.3%Died or euthanised
14 daysTypical onset
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How soon it started

Same day
13 11%
1–2 days
20 17%
3–7 days
12 10%
1–4 weeks
27 23%
Over a month
43 37%

How the animals did

Recovered
33 22%
Recovered with lasting effects
1 0.7%
Still unwell when reported
41 27%
Died
7 4.7%
Euthanised
7 4.7%
Not known
61 41%

Problems reported at the same time

Age of the animals

Under 1 year
18
1–3 years
29
4–7 years
28
8–11 years
56
12+ years
17

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 urinary tract infection in dogs?
150 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 14 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).

Urinary tract infection with similar medicines

All reported side effects of Afoxolaner in dogs · Medicines most reported with urinary tract infection