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

Area of Science:

• Nephrology
• Clinical Chemistry
• Pharmacology

Background:

• Urinary crystals are common findings in sediment analysis.
• Drug-induced crystalluria presents diagnostic challenges, especially with comorbidities.
• Methadone is a widely used opioid for chronic pain and opioid use disorder.

Purpose of the Study:

• To report the first case of 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidene (EDDP) crystals in urine.
• To highlight the diagnostic implications of drug metabolites in urinary sediment.
• To emphasize the importance of identifying drug-induced crystals in patients with complex medical conditions.

Main Methods:

• Routine urinalysis for crystal detection.
• Advanced spectroscopic techniques including Raman spectroscopy.
• Mass spectrometry for definitive crystal identification.

Main Results:

• Identification of needle-shaped crystals in the urine sediment of a patient on methadone therapy.
• Confirmation of these crystals as EDDP, the primary metabolite of methadone.
• The patient presented with hepatorenal syndrome, complicating the clinical picture.

Conclusions:

• This case represents the first documented instance of EDDP crystalluria.
• Meticulous urine sediment analysis is crucial for diagnosing drug-induced kidney injury.
• Recognizing drug metabolites as urinary crystals broadens the understanding of drug-induced nephrotoxicity.