Fever after Lotilaner (Credelio) in dogs

The FDA has received 129 reports of fever in dogs after Lotilaner. That is 1.3% of all reports for this medicine, compared with 1.4% across reports for all dog medicines.

129Reports
46%Marked serious
26%Recovered
12%Died or euthanised
28 daysTypical onset
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How soon it started

Same day
20 19%
1–2 days
12 12%
3–7 days
7 6.8%
1–4 weeks
16 16%
Over a month
48 47%

How the animals did

Recovered
33 26%
Recovered with lasting effects
1 0.8%
Still unwell when reported
42 33%
Died
8 6.2%
Euthanised
7 5.4%
Not known
38 29%

Problems reported at the same time

Age of the animals

Under 1 year
42
1–3 years
37
4–7 years
31
8–11 years
10
12+ years
9

About this medicine

Lotilaner kills fleas and ticks; monthly chewable.

Products with this ingredient include Credelio. 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 Lotilaner cause fever in dogs?
129 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 28 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).

Fever with similar medicines

All reported side effects of Lotilaner in dogs · Medicines most reported with fever