An analysis of green discoloration of urine caused by propofol infusion.

Background: Propofol is a short-acting, intravenous sedative-hypnotic agent that is widely used for the induction and maintenance of general anesthesia and sedation. An uncommon adverse effect of propofol is green discoloration of the urine, which has been reported not only under general anesthesia but also with sedation. Although it is assumed that the phenolic derivatives of propofol can cause green discoloration of the urine, the actual origin remains unknown. The aim of this report was to identify the origin of the green discoloration of the urine using liquid chromatography-mass spectrometry (LC-MS).

Clinical Features: The patient, a 51-year-old man, was scheduled for his oral surgery under general anesthesia using propofol. Postoperatively, the color of his urine was observed to be green. We compared and analyzed both the green urine and the normal urine using LC-MS.

Conclusion: We experienced a case of a patient with green discoloration of the urine after general anesthesia using propofol. Although LC-MS analysis showed 2 unique peaks in the green urine at 490 and 590 nm, obvious causes were not revealed.