Allergic reaction after Imidacloprid + Moxidectin (Advantage Multi) in cats

The FDA has received 35 reports of allergic reaction in cats after Imidacloprid + Moxidectin. That is 0.4% of all reports for this medicine, compared with 0.9% across reports for all cat medicines, so it is reported less often than average with this medicine.

35Reports
63%Marked serious
34%Recovered
17%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
8 38%
1–2 days
5 24%
3–7 days
3 14%
1–4 weeks
0 0.0%
Over a month
5 24%

How the animals did

Recovered
12 34%
Still unwell when reported
4 11%
Died
5 14%
Euthanised
1 2.9%
Not known
13 37%

Problems reported at the same time

Age of the animals

Under 1 year
11
1–3 years
4
4–7 years
12
8–11 years
3
12+ years
4

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 allergic reaction in cats?
35 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).

Allergic reaction with similar medicines

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