Lethargy after Imidacloprid + Moxidectin (Advantage Multi) in cats

1,394 reports to the FDA describe lethargy in cats given Imidacloprid + Moxidectin. That is 17% of all reports for this medicine, compared with 14% across reports for all cat medicines.

1,394Reports

58%Marked serious

36%Recovered

8.7%Died or euthanised

Same dayTypical onset

How soon it started

Same day

472 50%

1–2 days

299 32%

3–7 days

67 7.1%

1–4 weeks

67 7.1%

Over a month

36 3.8%

How the animals did

Recovered

497 36%

Recovered with lasting effects

2 0.1%

Still unwell when reported

49 3.5%

Died

86 6.2%

Euthanised

35 2.5%

Not known

725 52%

Problems reported at the same time

563 40%

294 21%

209 15%

201 14%

160 11%

131 9.4%

116 8.3%

113 8.1%

Age of the animals

Under 1 year

241

1–3 years

388

4–7 years

332

8–11 years

198

12+ years

165

About this medicine

Imidacloprid kills fleas (spot-on or collar). Moxidectin prevents heartworm disease (monthly topical, or a 6- or 12-month injection for dogs).

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

Questions owners ask

Can Imidacloprid + Moxidectin cause lethargy in cats?: 1,394 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 the same 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) 1,080 reports · 9.3% of its reports
Lethargy after Nitenpyram (Capstar) 926 reports · 11% of its reports
Lethargy after Lufenuron 236 reports · 21% of its reports
Lethargy after Flumethrin + Imidacloprid (Seresto) 72 reports · 11% of its reports
Lethargy after Imidacloprid + Pyriproxyfen 73 reports · 11% of its reports
Lethargy after Fipronil 62 reports · 12% of its reports
Lethargy after Fipronil + S-methoprene (Frontline Plus) 51 reports · 14% of its reports
Lethargy after Imidacloprid 33 reports · 13% of its reports

All reported side effects of Imidacloprid + Moxidectin in cats · Medicines most reported with lethargy