Loose stool after Metronidazole in dogs

157 reports to the FDA describe loose stool in dogs given Metronidazole. That is 5.1% of all reports for this medicine, compared with 0.9% across reports for all dog medicines, so it is reported unusually often with this medicine.

157Reports

56%Marked serious

13%Recovered

20%Died or euthanised

13 daysTypical onset

How soon it started

Same day

21 17%

1–2 days

21 17%

3–7 days

11 8.9%

1–4 weeks

30 24%

Over a month

41 33%

How the animals did

Recovered

17 11%

Recovered with lasting effects

3 1.9%

Still unwell when reported

82 52%

Died

8 5.1%

Euthanised

23 15%

Not known

24 15%

Problems reported at the same time

87 55%

78 50%

64 41%

44 28%

44 28%

32 20%

30 19%

28 18%

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 loose stool in dogs?: 157 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 13 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).

Loose stool with similar medicines

Loose stool after Amoxicillin + Clavulanate (Clavamox) 67 reports · 1.2% of its reports
Loose stool after Doxycycline 50 reports · 1.2% of its reports
Loose stool after Cefovecin (Convenia) 57 reports · 1.5% of its reports
Loose stool after Enrofloxacin (Baytril) 43 reports · 1.1% of its reports
Loose stool after Amoxicillin 23 reports · 1.7% of its reports

All reported side effects of Metronidazole in dogs · Medicines most reported with loose stool