Prolonged one stage prothrombin time (ospt) after Metronidazole in dogs

The FDA has received 21 reports of prolonged one stage prothrombin time (ospt) in dogs after Metronidazole. That is 0.7% of all reports for this medicine, compared with 0.0% across reports for all dog medicines, so it is reported unusually often with this medicine.

21Reports

90%Marked serious

14%Recovered

38%Died or euthanised

7 daysTypical onset

How soon it started

Same day

2 13%

1–2 days

1 6.3%

3–7 days

6 38%

1–4 weeks

5 31%

Over a month

2 13%

How the animals did

Recovered

2 9.5%

Recovered with lasting effects

1 4.8%

Still unwell when reported

10 48%

Died

2 9.5%

Euthanised

6 29%

Problems reported at the same time

Liver problems

17 81%

Vomiting

14 67%

Prolonged activated partial thrombin time (aptt)

14 67%

11 52%

11 52%

10 48%

9 43%

8 38%

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 prolonged one stage prothrombin time (ospt) in dogs?: 21 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 7 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).

Prolonged one stage prothrombin time (ospt) with similar medicines

Prolonged one stage prothrombin time (ospt) after Amoxicillin + Clavulanate (Clavamox) 20 reports · 0.4% of its reports

All reported side effects of Metronidazole in dogs · Medicines most reported with prolonged one stage prothrombin time (ospt)