Lethargy after Amoxicillin in cats

The FDA has received 105 reports of lethargy in cats after Amoxicillin. That is 20% of all reports for this medicine, compared with 14% across reports for all cat medicines.

105Reports

43%Marked serious

13%Recovered

24%Died or euthanised

1 daysTypical onset

How soon it started

Same day

27 36%

1–2 days

19 26%

3–7 days

10 14%

1–4 weeks

16 22%

Over a month

2 2.7%

How the animals did

Recovered

14 13%

Still unwell when reported

19 18%

Died

16 15%

Euthanised

9 8.6%

Not known

47 45%

Problems reported at the same time

56 53%

39 37%

25 24%

17 16%

15 14%

15 14%

13 12%

12 11%

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 lethargy in cats?: 105 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 1 day 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).

Lethargy with similar medicines

Lethargy after Cefovecin (Convenia) 2,068 reports · 24% of its reports
Lethargy after Amoxicillin + Clavulanate (Clavamox) 422 reports · 18% of its reports
Lethargy after Enrofloxacin (Baytril) 180 reports · 11% of its reports
Lethargy after Metronidazole 93 reports · 24% of its reports
Lethargy after Doxycycline 81 reports · 31% of its reports

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