title: The bioavailability of rectally administered morphine.
abstract: Plasma concentrations of morphine were followed for 24 hours in eight patients after intravenous and rectal administration of 10 mg morphine chloride. The plasma levels of morphine were determined by a sensitive and specific radioimmunoassay based upon an extraction procedure which separates morphine from its major polar metabolites. The bioavailability of morphine after rectal administration was found to be 53.3 +/- 17.8% (mean +/- S.D.). Peak concentrations of 16.3 +/- 8.7 ng ml-1 were reached after 59 +/- 16 min. The study indicates that first pass elimination of morphine may be partially avoided by rectal administration.
authors.affiliation: Department of Anaesthesia, Finsen Institute, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Jonsson
authors.forename: C B
authors.initials: CB
authors.lastname: Christensen
authors.forename: H
authors.initials: H
authors.lastname: Jordening
authors.forename: C
authors.initials: C
authors.lastname: Frølund
mesh_terms: D000285:Administration, Rectal; D000328:Adult; D000368:Aged; D001682:Biological Availability; D006801:Humans; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013488:Suppositories
chemical_list: D013488:Suppositories; D009020:Morphine