Methadone metabolite (EDDP) crystals in urine: a case report

Crystals in urinary sediment are commonly recognized structures, typically identified by a combination of crystal morphology and urine pH. In this paper, we present the first reported case of EDDP (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidene) crystals, the primary metabolite of methadone, in a 67-year-old male with hepatorenal syndrome. Routine urinalysis revealed numerous needle-shaped crystals, which prompted further investigation. Advanced techniques, including Raman spectroscopy and mass spectrometry, confirmed the crystals to be EDDP. This case highlights the diagnostic challenge posed by drug-induced crystalluria, particularly in the context of complex comorbidities and chronic opioid therapy. Early recognition and identification of such crystals are crucial to preventing further kidney injury, emphasizing the importance of meticulous urine sediment analysis in clinical practice. This report broadens the spectrum of drugs known to induce crystal formation.