Brief Answer:
Yes metronidazole can cause darkening of urine.

Detailed Answer:

Hi,

Yes metronidazole has a side effect to cause dark color urine. This is not very common but for sure it can cause it. This effect does not mean any thing serious, and we do not stop the drug for this reason unless you have other problems with the drug. I will encourage you to take more fluids.

However drugs are not the only cause for dark urine. Diet like beans, berries or dehydration can also cause dark urine.
similarly blood in urine that can occur with urinary tract infection may also cause dark urine.

But if you are other wise fine and didn't have this before the drug was started; then we can assume this is because of metronidazole.

Hope this help you understand your query. Let me know if you have any thing else to know. I will be glad to answer any further question.
Regards,
Dr. Rahman

---