British journal of clinical pharmacology
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Br J Clin Pharmacol · Aug 2004
Randomized Controlled Trial Comparative Study Clinical TrialBioavailabilities of rectal and oral methadone in healthy subjects.
Rectal administration of methadone may be an alternative to intravenous and oral dosing in cancer pain, but the bioavailability of the rectal route is not known. The aim of this study was to compare the absolute rectal bioavailability of methadone with its oral bioavailability in healthy humans. ⋯ Rectal administration of methadone results in rapid absorption, a high bioavailability and long duration of action. No evidence of presystemic elimination was seen. Rectal methadone has characteristics that make it a potential alternative to intravenous and oral administration, particularly in cancer pain and palliative care.