Weight loss after Amoxicillin in cats

The FDA has received 39 reports of weight loss in cats after Amoxicillin. That is 7.6% of all reports for this medicine, compared with 4.6% across reports for all cat medicines, so it is reported unusually often with this medicine.

39Reports

79%Marked serious

10%Recovered

36%Died or euthanised

8 daysTypical onset

How soon it started

Same day

7 22%

1–2 days

4 13%

3–7 days

4 13%

1–4 weeks

13 41%

Over a month

4 13%

How the animals did

Recovered

4 10%

Still unwell when reported

11 28%

Died

10 26%

Euthanised

4 10%

Not known

10 26%

Problems reported at the same time

28 72%

17 44%

17 44%

14 36%

14 36%

9 23%

Dehydration

8 21%

Fever

6 15%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Amoxicillin treats bacterial infections.

Questions owners ask

Can Amoxicillin cause weight loss in cats?: 39 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 8 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 Cefovecin (Convenia) 768 reports · 8.8% of its reports
Weight loss after Amoxicillin + Clavulanate (Clavamox) 139 reports · 5.8% of its reports
Weight loss after Enrofloxacin (Baytril) 60 reports · 3.8% of its reports
Weight loss after Metronidazole 62 reports · 16% of its reports
Weight loss after Doxycycline 28 reports · 11% of its reports

All reported side effects of Amoxicillin in cats · Medicines most reported with weight loss