Weakness after Imidacloprid + Moxidectin (Advantage Multi) in cats

56 reports to the FDA describe weakness in cats given Imidacloprid + Moxidectin. That is 0.7% of all reports for this medicine, compared with 1.2% across reports for all cat medicines, so it is reported less often than average with this medicine.

56Reports
71%Marked serious
27%Recovered
23%Died or euthanised
1 daysTypical onset
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How soon it started

Same day
13 33%
1–2 days
15 38%
3–7 days
5 13%
1–4 weeks
5 13%
Over a month
1 2.6%

How the animals did

Recovered
15 27%
Still unwell when reported
3 5.4%
Died
9 16%
Euthanised
4 7.1%
Not known
25 45%

Problems reported at the same time

Age of the animals

Under 1 year
12
1–3 years
12
4–7 years
10
8–11 years
10
12+ years
12

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 weakness in cats?
56 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).

Weakness with similar medicines

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