Swelling after Imidacloprid + Moxidectin (Advantage Multi) in cats

The FDA has received 72 reports of swelling in cats after Imidacloprid + Moxidectin. That is 0.9% of all reports for this medicine, compared with 1.9% across reports for all cat medicines, so it is reported less often than average with this medicine.

72Reports
60%Marked serious
26%Recovered
24%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
20 40%
1–2 days
13 26%
3–7 days
5 10%
1–4 weeks
11 22%
Over a month
1 2.0%

How the animals did

Recovered
18 25%
Recovered with lasting effects
1 1.4%
Still unwell when reported
5 6.9%
Died
11 15%
Euthanised
6 8.3%
Not known
31 43%

Problems reported at the same time

Age of the animals

Under 1 year
15
1–3 years
26
4–7 years
15
8–11 years
7
12+ years
8

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 swelling in cats?
72 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).

Swelling with similar medicines

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