Decreased haematocrit after Metronidazole in dogs

41 reports to the FDA describe decreased haematocrit in dogs given Metronidazole. That is 1.3% 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.

41Reports

83%Marked serious

12%Recovered

27%Died or euthanised

31 daysTypical onset

How soon it started

Same day

1 3.1%

1–2 days

4 13%

3–7 days

3 9.4%

1–4 weeks

8 25%

Over a month

16 50%

How the animals did

Recovered

5 12%

Still unwell when reported

13 32%

Died

1 2.4%

Euthanised

10 24%

Not known

12 29%

Problems reported at the same time

29 71%

23 56%

22 54%

21 51%

18 44%

16 39%

16 39%

Decreased red blood cell count

15 37%

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 decreased haematocrit in dogs?: 41 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 31 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).

Decreased haematocrit with similar medicines

Decreased haematocrit after Amoxicillin + Clavulanate (Clavamox) 48 reports · 0.9% of its reports
Decreased haematocrit after Doxycycline 38 reports · 0.9% of its reports
Decreased haematocrit after Enrofloxacin (Baytril) 40 reports · 1.1% of its reports

All reported side effects of Metronidazole in dogs · Medicines most reported with decreased haematocrit