These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: First-pass effect of morphine in rats.
    Author: Iwamoto K, Klaassen CD.
    Journal: J Pharmacol Exp Ther; 1977 Jan; 200(1):236-44. PubMed ID: 833759.
    Abstract:
    In order to evaluate the first-pass effect of morphine, the pharmacokinetic parameters of 3H-morphine (5 mg/kg) were studied in male Sprague-Dawley rats by comparing the plasma concentrations after oral, intravenous and intraportal administration. Morphine was almost completely absorbed from the gastrointestinal tract, since no significant difference was found in the cumulative urinary excretion of radioactivity after intravenous and oral administration. Route of administration had no affect on plasma half-life (about 115 minutes) of unchanged morphine. In contrast, the area under the plasma concentration vs. time curve for morphine after oral administration was only about 18%, and after intraportal administration about 40% of that observed after intravenous administration. It can be estimated that approximately two-thirds of the overall first-pass effect (82%) of morphine is due to extraction and/or metabolism in the intestine and the remaining one-third by the liver.
    [Abstract] [Full Text] [Related] [New Search]