Loose stool after Imidacloprid + Moxidectin (Advantage Multi) in dogs

The FDA has received 161 reports of loose stool in dogs after Imidacloprid + Moxidectin. That is 1.2% of all reports for this medicine, compared with 0.9% across reports for all dog medicines.

161Reports

66%Marked serious

30%Recovered

3.1%Died or euthanised

7 daysTypical onset

How soon it started

Same day

21 19%

1–2 days

26 24%

3–7 days

12 11%

1–4 weeks

35 32%

Over a month

14 13%

How the animals did

Recovered

49 30%

Still unwell when reported

11 6.8%

Died

4 2.5%

Euthanised

1 0.6%

Not known

96 60%

Problems reported at the same time

46 29%

45 28%

29 18%

29 18%

Didn't work as expected

28 17%

Loss of appetite

25 16%

Behaviour change

14 8.7%

Restlessness or agitation

11 6.8%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 loose stool in dogs?: 161 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 7 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).

Loose stool with similar medicines

Loose stool after Spinosad (Comfortis) 236 reports · 0.4% of its reports
Loose stool after Lufenuron + Milbemycin Oxime (Sentinel) 315 reports · 1.2% of its reports
Loose stool after Nitenpyram (Capstar) 89 reports · 0.8% of its reports
Loose stool after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 116 reports · 1.2% of its reports
Loose stool after Fipronil + S-methoprene (Frontline Plus) 35 reports · 1.2% of its reports
Loose stool after Fipronil 21 reports · 1.5% of its reports

All reported side effects of Imidacloprid + Moxidectin in dogs · Medicines most reported with loose stool