Key interindividual determinants in MDMA pharmacodynamics

Introduction

MDMA (3,4-methylenedioxymethamphetamine) is a synthetic phenethylamine with pharmacological similarities to amphetamines and mescaline that produces stimulant and empathogenic effects such as euphoria, increased sociability and enhanced empathy. After early therapeutic interest in the 1970s it became a widely used recreational drug from the 1980s onwards and is currently among the most prevalent illicit stimulants globally. Controlled human studies report sympathomimetic physiological effects (increases in blood pressure, heart rate and temperature), neuroendocrine changes (including cortisol, arginine‑vasopressin and oxytocin), and a plasma pharmacokinetic profile characterised by Tmax around 2 hours and an elimination half‑life of roughly 8–9 hours; MDMA is metabolised via N‑demethylation to MDA and further O‑demethylenation and O‑methylation steps involving COMT and multiple CYP450 isoenzymes. Papaseit and colleagues set out to review the main interindividual determinants of MDMA pharmacodynamics, emphasising sex‑gender, race‑ethnicity, genetic polymorphisms (particularly CYP450 variants and COMT), interactions (polydrug use and concomitant medications), and factors linked to acute toxicity. The review focuses on experimental human studies and clinical intoxication reports to identify sources of variability relevant for both recreational risk and potential therapeutic applications.