Tuesday January 15, 2008


Scenario: 79 year old male, nursing home resident, with abdominal pain, nausea, vomiting, and diarrhea is admitted to ICU with significant hemodynamic instability. While reviewing previous discharge summaries, you found multiple reports of positive stool for 'C.Diff.' with successful treatment with 'flagyl'. You started patient on appropriate broad range antibiotics including flagyl. Patient responded well to treatment and is getting transfer out of ICU after 2 days but before transfer you received strange call from nurse - that patient's urine is black ! Will you hold the transfer ?



Answer: NO

Metronidazole (Flagyl) induced change of urine color.

Black urine is a rare but benign side effect of Flagyl. The actual metabolite responsible for this phenomenon has not been positively identified yet but fortunately it has no clinical significance.


Related article: The Significance of Abnormal Urine Color

(Martha K. Terris, M.D., Assistant Professor of Urology, Chief of Urology, Veterans Affairs Palo Alto Health Care System)