Weight loss after Metronidazole in dogs

The FDA has received 265 reports of weight loss in dogs after Metronidazole. That is 8.6% of all reports for this medicine, compared with 1.7% across reports for all dog medicines, so it is reported unusually often with this medicine.

265Reports

75%Marked serious

11%Recovered

31%Died or euthanised

8 daysTypical onset

How soon it started

Same day

42 19%

1–2 days

29 13%

3–7 days

35 16%

1–4 weeks

46 21%

Over a month

69 31%

How the animals did

Recovered

25 9.4%

Recovered with lasting effects

3 1.1%

Still unwell when reported

110 42%

Died

29 11%

Euthanised

54 20%

Not known

44 17%

Problems reported at the same time

169 64%

149 56%

147 55%

123 46%

116 44%

84 32%

72 27%

49 18%

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 loss in dogs?: 265 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 8 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 loss with similar medicines

Weight loss after Amoxicillin + Clavulanate (Clavamox) 249 reports · 4.6% of its reports
Weight loss after Doxycycline 207 reports · 5.2% of its reports
Weight loss after Cefovecin (Convenia) 167 reports · 4.4% of its reports
Weight loss after Enrofloxacin (Baytril) 186 reports · 4.9% of its reports
Weight loss after Amoxicillin 113 reports · 8.4% of its reports

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