Crust after Imidacloprid + Moxidectin (Advantage Multi) in cats

29 reports to the FDA describe crust in cats given Imidacloprid + Moxidectin. That is 0.4% of all reports for this medicine, compared with 0.3% across reports for all cat medicines.

29Reports

86%Marked serious

24%Recovered

0.0%Died or euthanised

11 daysTypical onset

How soon it started

Same day

1 4.8%

1–2 days

2 9.5%

3–7 days

5 24%

1–4 weeks

7 33%

Over a month

6 29%

How the animals did

Recovered

7 24%

Still unwell when reported

1 3.4%

Not known

21 72%

Problems reported at the same time

Skin rash or irritation

15 52%

Skin redness

13 45%

Hair loss

12 41%

Itching

9 31%

Application site reaction

9 31%

Skin inflammation

7 24%

Papule

6 21%

Skin scab

4 14%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 crust in cats?: 29 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).

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