Weight gain after Metronidazole in dogs

The FDA has received 28 reports of weight gain in dogs after Metronidazole. That is 0.9% of all reports for this medicine, compared with 0.6% across reports for all dog medicines.

28Reports

86%Marked serious

11%Recovered

32%Died or euthanised

4 daysTypical onset

How soon it started

Same day

4 19%

1–2 days

6 29%

3–7 days

1 4.8%

1–4 weeks

3 14%

Over a month

7 33%

How the animals did

Recovered

1 3.6%

Recovered with lasting effects

2 7.1%

Still unwell when reported

6 21%

Died

1 3.6%

Euthanised

8 29%

Not known

10 36%

Problems reported at the same time

16 57%

16 57%

14 50%

12 43%

9 32%

9 32%

9 32%

8 29%

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 weight gain in dogs?: 28 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 4 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).

Weight gain with similar medicines

Weight gain after Amoxicillin + Clavulanate (Clavamox) 28 reports · 0.5% of its reports
Weight gain after Doxycycline 56 reports · 1.4% of its reports
Weight gain after Cefovecin (Convenia) 21 reports · 0.6% of its reports
Weight gain after Enrofloxacin (Baytril) 26 reports · 0.7% of its reports

All reported side effects of Metronidazole in dogs · Medicines most reported with weight gain