Board Review: Methadone Intoxication

Originally Published: Modern Resident, Jun/Jul 2010

Original Author: Dana Kindermann, MD Georgetown-Washington Hospital Center Dept. of Emergency Medicine

Submitted by: Saadiyah Bilal, Publications Committee, Co-Chair 

Case history:
56 y/o male BIBA, found in apartment by roommate with altered mental status x 24h, found lying in feces. Patient (pt) with multiple substance abuse related admissions and ED visits. On arrival, pt slow to respond, confused, A&O x 2, denies pain, takes 150mg PO methadone daily, denies other med/drug use. Initial EKG: QTc – 500ms, bigeminy. Pt loaded with IV Mg, IV fluids; all initial labs normal and pt transferred to floor. Three hours later, pt develops Torsades de Pointes (TdP).

About Methadone

  • Long acting synthetic opiod used for chronic pain, opiod dependence
  • Multiple case reports of methadone-associated QT prolongation
  • Other than Levoacetlymethadol (longer acting methadone-like opiod), no other opiods thought to cause QTc prolongation
About Prolonged QTc
  • Pt may be asymptomatic, have palpitations, syncope, seizures, cardiac arrest
  • Trait is inherited or acquired (common drugs – antibiotics, antidepressants, antihistamines, diuretics, heart medications, antipsychotics)
Risk Factors Associated with QTc Prolongation and TdP
  • Females, hypokalemia, polypharmacy, underlying cardiac conditions, congenital prolonged QT syndrome
Risk Factors for Methadone-Associated TdP
  • DOSE (>60mg/day), HIV, hypokalemia (acutely – vomiting, diarrhea, dehydration, diuretic use), polypharmacy, females, cirrhosis, renal failure, heart disease
Acute Management of Methadone-Associated TdP
  • Stop methadone
  • IV fluids
  • Electrolyte monitoring/correction
  • IV Mg
  • +/- Cardiac pacing
Long-term Management of Methadone-Associated Arrhythmias
  • Switch to alternate drug (other opiod if for pain control, Buprenorphine if for opiod addiction); or try lower dose of methadone
  • ICD placement


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  2. Justo D, Gal-Oz A, Paran Y, et al. Methadone-associated torsades de pointes (polymorphic ventricular tachycardia) in opioid-dependent patients. Addiction. 2006; 101:1333-8.58.
  3. Stringer J, Welsh C, Tommasello A. Methadone-associated Q-T interval prolongation and torsades de pointes. Am J Health-Syst Pharm. 2009; 66(9): 825-832.