Docs baffled...

“An old drug cimetidine [used to treat acidity] and certain antidepressants are known to cause green discolouration of urine,” said Shah, adding that it was possible that the change in colour could be due to a condition known as myoglobinuria (release of a protein myglobinuria in blood due to muscle damage).

Finally, Choudhury and his colleagues realised that the patient was having an extremely rare reaction to the intravenous anaesthetic drug, propofol. There are only two recorded cases in medical literature of a patient reacting to propofol by discharging green urine.

The patient and his urine were closely monitored for the next three days, after which the latter returned to its normal colour. He has since been discharged and is recovering “very well”.

Since the incidence of green urine is so rare, Choudhury and his two colleagues decided to write up a report of this case, which was published in the June 10 issue of British Medical Journal. Their article was accompanied by a picture of a labelled container containing the dark green urine.

“Since neither did the patient suffer from UTI nor did any of the drugs received by him were known to cause green urine, we finally suspected that propofol, a drug which was used for general anaesthesia would be the sole reason,” wrote the doctors in their report. “Return of the urine to its normal colour coupled with a normal urinalysis confirmed our suspicion of propofol being the cause of the phenomena.”

Propofol is a commonly used sedative agent of general anesthesia, but urine discolouration after propofol infusion and its clinical association is not widely known to clinicians because of its rare occurrence. “It’s unusual and can lead to confusion and anxiety,” wrote the doctors. “Though rare, it is benign and has little significance if not caused by urinary tract infections, so nursing staff and patients should be warned about this clinical finding to avoid any anxiety among them.”