Blood in stool after Metronidazole in dogs

79 reports to the FDA describe blood in stool in dogs given Metronidazole. That is 2.6% of all reports for this medicine, compared with 0.6% across reports for all dog medicines, so it is reported unusually often with this medicine.

79Reports

77%Marked serious

15%Recovered

35%Died or euthanised

2 daysTypical onset

How soon it started

Same day

23 34%

1–2 days

14 21%

3–7 days

7 10%

1–4 weeks

13 19%

Over a month

11 16%

How the animals did

Recovered

12 15%

Still unwell when reported

33 42%

Died

7 8.9%

Euthanised

21 27%

Not known

6 7.6%

Problems reported at the same time

55 70%

48 61%

39 49%

34 43%

30 38%

28 35%

22 28%

Abnormal ultrasound finding

16 20%

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 blood in stool in dogs?: 79 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).

Blood in stool with similar medicines

Blood in stool after Amoxicillin + Clavulanate (Clavamox) 75 reports · 1.4% of its reports
Blood in stool after Doxycycline 30 reports · 0.7% of its reports
Blood in stool after Cefovecin (Convenia) 38 reports · 1.0% of its reports
Blood in stool after Enrofloxacin (Baytril) 43 reports · 1.1% of its reports
Blood in stool after Amoxicillin 23 reports · 1.7% of its reports

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