CriticalClass III antiarrhythmics (Vaughan Williams)×Synthetic opioid, full mu-receptor agonist
Updated · Methodology
Mechanism
Additive QT prolongation from two strong QT prolongers + amiodarone inhibits CYP3A4 (methadone rises).
Symptoms
QTc above 500 ms, syncope, torsades de pointes risk.
Management
Combination contraindicated.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- FDA: Amiodarone hydrochloride tablet (Dr. Reddy's Labratories Inc.) – Prescribing Information (2018)– ; DailyMed setid 95cef33b-c0e6-b17c-7cbb-f5c066872705
- FDA: Methadone hydrochloride tablet (Vistapharm, LLC) – Prescribing Information – QT prolongation and CYP interactions (2014)– FDA Dolophine label, Boxed Warning – QT prolongation, serious cardiac arrhythmias; DailyMed setid c54baaee-8ea4-45f5-a5c8-bb84cf86832f
- FDA: Methadone hydrochloride tablets (SpecGx) – Prescribing Information (2014)
- AEMPS: Ficha técnica: Metadona (nº registro 62423), sección 4.5 (2026)– AEMPS, CIMA, nº registro 62423, sección 4.5