Keeping patients safe from methadone overdoses.

462 P&T® • August 2011 • Vol. 36 No. 8 one to five hours).1 • The half-life of methadone in an opioid-tolerant patient is approximately 24 hours; its half-life in an opioidnaive patient is approximately 55 hours. Therefore, the duration of effect is extended in opioid-naive patients.2 • Owing to methadone’s long half-life, full analgesic effects might not be attained until after three to five days of use. Therefore, the dose must be titrated more slowly than that of other opioids.1 • Methadone’s peak respiratory depressant effects typically occur later and persist longer than its peak analgesic effects.1