Weight loss after Imidacloprid + Pyriproxyfen in cats

29 reports to the FDA describe weight loss in cats given Imidacloprid + Pyriproxyfen. That is 4.4% of all reports for this medicine, compared with 4.6% across reports for all cat medicines.

29Reports

76%Marked serious

17%Recovered

21%Died or euthanised

14 daysTypical onset

How soon it started

Same day

1 5.9%

1–2 days

0 0.0%

3–7 days

5 29%

1–4 weeks

8 47%

Over a month

3 18%

How the animals did

Recovered

5 17%

Still unwell when reported

2 6.9%

Died

3 10%

Euthanised

3 10%

Not known

16 55%

Problems reported at the same time

13 45%

13 45%

9 31%

8 28%

7 24%

7 24%

6 21%

6 21%

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).

Questions owners ask

Can Imidacloprid + Pyriproxyfen cause weight loss in cats?: 29 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 14 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 loss with similar medicines

Weight loss after Spinosad (Comfortis) 166 reports · 1.4% of its reports
Weight loss after Nitenpyram (Capstar) 99 reports · 1.1% of its reports
Weight loss after Imidacloprid + Moxidectin (Advantage Multi) 188 reports · 2.3% of its reports
Weight loss after Lufenuron 53 reports · 4.8% of its reports
Weight loss after Flumethrin + Imidacloprid (Seresto) 35 reports · 5.2% of its reports

All reported side effects of Imidacloprid + Pyriproxyfen in cats · Medicines most reported with weight loss