What should a nurse inform a client about the darkening of urine while taking metronidazole (Flagyl)?

The darkening of urine while taking metronidazole is considered a harmless side effect. This occurs due to the way the drug is metabolized in the body and subsequently excreted. Metronidazole can cause changes in urine color as it is processed, reflecting alterations in the body's handling of the medication rather than indicating a serious health concern. In clinical practice, it's important to reassure clients that this coloration does not signify toxicity, an overdose, or liver dysfunction, allowing them to continue their treatment without unnecessary alarm about this benign effect.