Overdose after Imidacloprid + Moxidectin (Advantage Multi) in cats

The FDA has received 164 reports of overdose in cats after Imidacloprid + Moxidectin. That is 2.0% of all reports for this medicine, compared with 0.9% across reports for all cat medicines, so it is reported unusually often with this medicine.

164Reports
54%Marked serious
38%Recovered
1.8%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
41 42%
1–2 days
18 19%
3–7 days
9 9.3%
1–4 weeks
23 24%
Over a month
6 6.2%

How the animals did

Recovered
63 38%
Died
2 1.2%
Euthanised
1 0.6%
Not known
98 60%

Problems reported at the same time

Age of the animals

Under 1 year
45
1–3 years
52
4–7 years
30
8–11 years
13
12+ years
18

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 overdose in cats?
164 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).

Overdose with similar medicines

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