Lethargy after Metronidazole in cats

The FDA has received 93 reports of lethargy in cats after Metronidazole. That is 24% of all reports for this medicine, compared with 14% across reports for all cat medicines, so it is reported unusually often with this medicine.

93Reports

56%Marked serious

28%Recovered

19%Died or euthanised

2 daysTypical onset

How soon it started

Same day

22 28%

1–2 days

19 24%

3–7 days

12 15%

1–4 weeks

20 26%

Over a month

5 6.4%

How the animals did

Recovered

25 27%

Recovered with lasting effects

1 1.1%

Still unwell when reported

24 26%

Died

9 9.7%

Euthanised

9 9.7%

Not known

25 27%

Problems reported at the same time

48 52%

39 42%

25 27%

17 18%

17 18%

14 15%

12 13%

11 12%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Metronidazole treats some bacterial and parasitic gut infections.

Questions owners ask

Can Metronidazole cause lethargy in cats?: 93 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 2 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).

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 Amoxicillin 105 reports · 20% of its reports
Lethargy after Doxycycline 81 reports · 31% of its reports

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