Applying legal risk management to the clinical use of methadone.

tion was removed in 1976; physicians with appropriate Drug Enforcement Agency registration may now prescribe methadone for analgesia.3 The unique pharmaco kinetic and pharmacodynamic characteristics of methadone make it a valuable option for the management of chronic pain both as a first-line agent and as a replacement opioid.1,4 Even though methadone may be administered by several routes––oral, rectal, intravenous, intramuscular, subcutaneous, epidural, and intrathecal–– it is most commonly given orally in either tablets or solution.1,5 Numerous evaluations of methadone, including placebo-controlled clinical trials, have shown that it is an effective analgesic in cancer pain and in chronic non-cancer pain.1 Its pharmacological properties, however, demand greater precautions than are necessary with other opioids.6 Methadone has a long-elimination halflife (8–59 hours),7–9 which might not correlate with its duration of analgesic efficacy (typically 8–12 hours with repeated dosing).4 This pharmacokinetic property necessitates careful management and titration of effective dosing schedules, because the mismatch of half-life and duration of analgesia is potentially lifethreatening.10 Day-to-day monitoring is essential when chronic methadone therapy is initiated or when patients are switching from another opioid to methadone for pain relief.1