Original article Patient-controlled analgesia with oral methadone in cancer pain: Preliminary report

Background: Methadone is a very useful drug in cancer pain because of its low cost, lack of active metabolites, high oral availability, and the rapid onset of its analgesic effect. It seems to be well tolerated in patients with difficult pain syn-dromes who are receiving high doses of opioids, and it may deter the development of tolerance, but a high individual variation in terminal elimination half-life can result in differ-ent rates and extents of drug accumulation. For this reason, oral patient-controlled analgesia with methadone was used in 24 advanced-disease patients with pain. Patients and methods: A regimen of self-administered oral methadone at fixed doses and flexible patient-controlled dos-age intervals to achieve adequate analgesia, while avoiding toxic effects of methadone accumulation, was used in 24 patients requiring opioid therapy. After a priming period o