Lethargy after Lufenuron + Milbemycin Oxime (Sentinel) in dogs

The FDA has received 2,341 reports of lethargy in dogs after Lufenuron + Milbemycin Oxime. That is 9.0% of all reports for this medicine, compared with 11% across reports for all dog medicines.

2,341Reports

32%Marked serious

34%Recovered

6.2%Died or euthanised

1 daysTypical onset

How soon it started

Same day

429 40%

1–2 days

257 24%

3–7 days

64 6.0%

1–4 weeks

93 8.7%

Over a month

223 21%

How the animals did

Recovered

769 33%

Recovered with lasting effects

23 1.0%

Still unwell when reported

277 12%

Died

100 4.3%

Euthanised

46 2.0%

Not known

1,126 48%

Problems reported at the same time

913 39%

829 35%

520 22%

203 8.7%

191 8.2%

158 6.7%

143 6.1%

141 6.0%

Age of the animals

Under 1 year

459

1–3 years

689

4–7 years

617

8–11 years

393

12+ years

152

About this medicine

Lufenuron stops flea eggs from developing. Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly).

Products with this combination include Sentinel. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

Questions owners ask

Can Lufenuron + Milbemycin Oxime cause lethargy in dogs?: 2,341 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 1 day 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).

Lethargy with similar medicines

Lethargy after Spinosad (Comfortis) 7,303 reports · 13% of its reports
Lethargy after Imidacloprid + Moxidectin (Advantage Multi) 2,000 reports · 15% of its reports
Lethargy after Nitenpyram (Capstar) 1,204 reports · 11% of its reports
Lethargy after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 666 reports · 6.7% of its reports
Lethargy after Fipronil + S-methoprene (Frontline Plus) 447 reports · 15% of its reports
Lethargy after Flumethrin + Imidacloprid (Seresto) 250 reports · 11% of its reports
Lethargy after Imidacloprid 196 reports · 10% of its reports
Lethargy after Fipronil 185 reports · 13% of its reports
Lethargy after Lufenuron 205 reports · 20% of its reports
Lethargy after Imidacloprid + Permethrin + Pyriproxyfen 106 reports · 14% of its reports

All reported side effects of Lufenuron + Milbemycin Oxime in dogs · Medicines most reported with lethargy