Abnormal cytology after Metronidazole in dogs

40 reports to the FDA describe abnormal cytology in dogs given Metronidazole. That is 1.3% of all reports for this medicine, compared with 0.2% across reports for all dog medicines, so it is reported unusually often with this medicine.

40Reports

75%Marked serious

7.5%Recovered

28%Died or euthanised

31 daysTypical onset

How soon it started

Same day

2 6.7%

1–2 days

4 13%

3–7 days

5 17%

1–4 weeks

4 13%

Over a month

15 50%

How the animals did

Recovered

3 7.5%

Still unwell when reported

21 53%

Died

4 10%

Euthanised

7 18%

Not known

5 13%

Problems reported at the same time

19 48%

18 45%

17 43%

17 43%

15 38%

11 28%

10 25%

9 23%

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 abnormal cytology in dogs?: 40 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).

Abnormal cytology with similar medicines

Abnormal cytology after Amoxicillin + Clavulanate (Clavamox) 85 reports · 1.6% of its reports
Abnormal cytology after Doxycycline 59 reports · 1.5% of its reports
Abnormal cytology after Cefovecin (Convenia) 42 reports · 1.1% of its reports
Abnormal cytology after Enrofloxacin (Baytril) 57 reports · 1.5% of its reports

All reported side effects of Metronidazole in dogs · Medicines most reported with abnormal cytology