Increased packed cell volume (pcv) after Metronidazole in dogs

The FDA has received 26 reports of increased packed cell volume (pcv) in dogs after Metronidazole. That is 0.8% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

26Reports

81%Marked serious

3.8%Recovered

46%Died or euthanised

2 daysTypical onset

How soon it started

Same day

4 17%

1–2 days

8 35%

3–7 days

2 8.7%

1–4 weeks

5 22%

Over a month

4 17%

How the animals did

Recovered

1 3.8%

Still unwell when reported

11 42%

Died

9 35%

Euthanised

3 12%

Not known

2 7.7%

Problems reported at the same time

23 88%

21 81%

14 54%

13 50%

12 46%

10 38%

10 38%

9 35%

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 increased packed cell volume (pcv) in dogs?: 26 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).

All reported side effects of Metronidazole in dogs · Medicines most reported with increased packed cell volume (pcv)