Didn't stop fleas after Metronidazole in dogs

The FDA has received 21 reports of didn't stop fleas in dogs after Metronidazole. That is 0.7% of all reports for this medicine, compared with 6.2% across reports for all dog medicines, so it is reported less often than average with this medicine.

21Reports

24%Marked serious

19%Recovered

0.0%Died or euthanised

92 daysTypical onset

How soon it started

Same day

2 14%

1–2 days

0 0.0%

3–7 days

0 0.0%

1–4 weeks

2 14%

Over a month

10 71%

How the animals did

Recovered

2 9.5%

Recovered with lasting effects

2 9.5%

Still unwell when reported

3 14%

Not known

14 67%

Problems reported at the same time

Vomiting

6 29%

Didn't work as expected

4 19%

3 14%

3 14%

3 14%

3 14%

3 14%

3 14%

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 didn't stop fleas in dogs?: 21 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 92 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).

Didn't stop fleas with similar medicines

Didn't stop fleas after Amoxicillin + Clavulanate (Clavamox) 27 reports · 0.5% of its reports

All reported side effects of Metronidazole in dogs · Medicines most reported with didn't stop fleas