Didn't work as expected after Lotilaner (Credelio) in dogs

The FDA has received 1,497 reports of didn't work as expected in dogs after Lotilaner. That is 15% of all reports for this medicine, compared with 13% across reports for all dog medicines.

1,497Reports

8.7%Marked serious

1.4%Recovered

0.8%Died or euthanised

141 daysTypical onset

How soon it started

Same day

36 4.2%

1–2 days

15 1.8%

3–7 days

26 3.0%

1–4 weeks

123 14%

Over a month

656 77%

How the animals did

Recovered

21 1.4%

Still unwell when reported

112 7.5%

Died

8 0.5%

Euthanised

4 0.3%

Not known

1,352 90%

Problems reported at the same time

487 33%

70 4.7%

56 3.7%

56 3.7%

49 3.3%

48 3.2%

43 2.9%

30 2.0%

Age of the animals

Under 1 year

299

1–3 years

629

4–7 years

309

8–11 years

150

12+ years

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 work as expected in dogs?: 1,497 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 141 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 work as expected with similar medicines

Didn't work as expected after Fluralaner (Bravecto) 5,946 reports · 8.6% of its reports
Didn't work as expected after Afoxolaner (NexGard) 8,625 reports · 15% of its reports
Didn't work as expected after Sarolaner (Simparica) 1,487 reports · 8.9% of its reports
Didn't work as expected after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 1,527 reports · 16% of its reports
Didn't work as expected after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 292 reports · 9.5% of its reports

All reported side effects of Lotilaner in dogs · Medicines most reported with didn't work as expected