Hair loss after Imidacloprid + Moxidectin (Advantage Multi) in cats

1,437 reports to the FDA describe hair loss in cats given Imidacloprid + Moxidectin. That is 18% of all reports for this medicine, compared with 14% across reports for all cat medicines.

1,437Reports

58%Marked serious

29%Recovered

1.7%Died or euthanised

2 daysTypical onset

How soon it started

Same day

172 17%

1–2 days

407 41%

3–7 days

214 22%

1–4 weeks

133 13%

Over a month

63 6.4%

How the animals did

Recovered

411 29%

Still unwell when reported

55 3.8%

Died

12 0.8%

Euthanised

12 0.8%

Not known

947 66%

Problems reported at the same time

Application site reaction

583 41%

Itching

377 26%

Skin redness

316 22%

Skin rash or irritation

125 8.7%

Behaviour change

86 6.0%

Lethargy

78 5.4%

Restlessness or agitation

60 4.2%

Loss of appetite

55 3.8%

Age of the animals

Under 1 year

1–3 years

402

4–7 years

414

8–11 years

266

12+ years

153

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 hair loss in cats?: 1,437 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 2 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).

Hair loss with similar medicines

Hair loss after Spinosad (Comfortis) 76 reports · 0.7% of its reports
Hair loss after Nitenpyram (Capstar) 111 reports · 1.3% of its reports
Hair loss after Lufenuron 83 reports · 7.5% of its reports
Hair loss after Flumethrin + Imidacloprid (Seresto) 166 reports · 25% of its reports
Hair loss after Imidacloprid + Pyriproxyfen 83 reports · 13% of its reports
Hair loss after Fipronil 34 reports · 6.8% of its reports
Hair loss after Fipronil + S-methoprene (Frontline Plus) 39 reports · 11% of its reports
Hair loss after Imidacloprid 24 reports · 9.5% of its reports

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