The Adequateness of Methadone for Japanese Terminal Cancer Patients Can Be Determined Earlier than 7 Days: A Preliminary Retrospective Study.

The adequateness of methadone in Japanese terminal cancer patients could be determined before day 7, considering the high analgesia incidence and few adverse events 3 days after the methadone administration under careful observation by a physician experienced in methadone administration. However, as this is a preliminary study, the relationship between pharmacokinetic parameters and analgesic effects was not evaluated. Further studies involving pharmacokinetics and multicenter prospective studies are required to support these findings.