Didn't work as expected after Imidacloprid + Moxidectin (Advantage Multi) in cats

The FDA has received 63 reports of didn't work as expected in cats after Imidacloprid + Moxidectin. That is 0.8% of all reports for this medicine, compared with 8.7% across reports for all cat medicines, so it is reported less often than average with this medicine.

63Reports

37%Marked serious

19%Recovered

0.0%Died or euthanised

18 daysTypical onset

How soon it started

Same day

2 4.3%

1–2 days

3 6.5%

3–7 days

6 13%

1–4 weeks

18 39%

Over a month

17 37%

How the animals did

Recovered

11 17%

Recovered with lasting effects

1 1.6%

Still unwell when reported

4 6.3%

Not known

47 75%

Problems reported at the same time

22 35%

12 19%

9 14%

7 11%

5 7.9%

4 6.3%

Urinary tract infection

4 6.3%

Overdose

4 6.3%

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 didn't work as expected in cats?: 63 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 18 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).

Didn't work as expected with similar medicines

Didn't work as expected after Spinosad (Comfortis) 1,060 reports · 9.2% of its reports
Didn't work as expected after Nitenpyram (Capstar) 232 reports · 2.7% of its reports
Didn't work as expected after Imidacloprid + Pyriproxyfen 24 reports · 3.7% of its reports
Didn't work as expected after Fipronil 38 reports · 7.6% of its reports
Didn't work as expected after Fipronil + S-methoprene (Frontline Plus) 22 reports · 6.0% of its reports

All reported side effects of Imidacloprid + Moxidectin in cats · Medicines most reported with didn't work as expected