Didn't stop fleas after Lotilaner (Credelio) in cats

147 reports to the FDA describe didn't stop fleas in cats given Lotilaner. That is 16% of all reports for this medicine, compared with 8.4% across reports for all cat medicines, so it is reported unusually often with this medicine.

147Reports
4.1%Marked serious
0.7%Recovered
0.7%Died or euthanised
11 daysTypical onset
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How soon it started

Same day
18 13%
1–2 days
25 18%
3–7 days
16 12%
1–4 weeks
48 35%
Over a month
29 21%

How the animals did

Recovered
1 0.7%
Still unwell when reported
25 17%
Died
1 0.7%
Not known
120 82%

Problems reported at the same time

38 26%
4 2.7%
4 2.7%
Difficulty of use
3 2.0%

Age of the animals

Under 1 year
11
1–3 years
27
4–7 years
23
8–11 years
20
12+ years
16

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 didn't stop fleas in cats?
147 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 11 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).

Didn't stop fleas with similar medicines

All reported side effects of Lotilaner in cats · Medicines most reported with didn't stop fleas