An interesting observation: prolonged green urine can be a combined effect of decreased liver and renal function in a patient with heart failure-a case report.

Background: The administration of propofol and methylene blue (MB) can be associated with the appearance of prolonged green urine discoloration, particularly in patients with heart failure (HF) concomitant with renal and liver dysfunction. Understanding the reasons behind this phenomenon is of clinical significance.

Case Summary: A 79-year-old woman with a history of HF experienced dyspnoea and persistent green urine discoloration for a week, leading to her hospitalization for acutely decompensated HF. A recent dual-chamber rate-modulated-pacemaker implantation had necessitated propofol sedation and the administration of 100 mg of MB due to methaemoglobinaemia. Upon admission, the patient exhibited elevated levels of brain natriuretic peptide (BNP) and liver function tests, as well as a significant decrease in glomerular filtration rate (GFR). Initial therapy with intravenous furosemide yielded an inadequate response, requiring the initiation of combined diuretic therapy (CDT). The patient's condition improved with CDT, resulting in the normalization of BNP, liver function tests, and GFR, along with the restoration of normal urine colour lasting 12 days.

Discussion: Our case report sheds light on the complex interaction between drug metabolic pathways and their potential for prolonged side effects, particularly in patients with multiorgan dysfunction. The association between propofol, MB, and green urine discoloration in the context of HF warrants further investigation, emphasizing the need for increased awareness of drug interactions and their implications in complex clinical scenarios.