Weight gain after Imidacloprid + Moxidectin (Advantage Multi) in dogs

193 reports to the FDA describe weight gain in dogs given Imidacloprid + Moxidectin. That is 1.5% of all reports for this medicine, compared with 0.6% across reports for all dog medicines, so it is reported unusually often with this medicine.

193Reports
71%Marked serious
17%Recovered
3.1%Died or euthanised
27 daysTypical onset
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How soon it started

Same day
9 8.4%
1–2 days
8 7.5%
3–7 days
5 4.7%
1–4 weeks
38 36%
Over a month
47 44%

How the animals did

Recovered
31 16%
Recovered with lasting effects
1 0.5%
Still unwell when reported
11 5.7%
Euthanised
6 3.1%
Not known
144 75%

Problems reported at the same time

Age of the animals

Under 1 year
7
1–3 years
95
4–7 years
59
8–11 years
15
12+ years
6

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 weight gain in dogs?
193 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 27 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).

Weight gain with similar medicines

All reported side effects of Imidacloprid + Moxidectin in dogs · Medicines most reported with weight gain