Pharmacokinetic studies on the selectiveβ1-receptor antagonist metoprolol in man

  • Carl G. Regårdh
  • Karl O. Borg
  • Rustan Johansson
  • Gillis Johnsson
  • Lars Palmer


The pharmacokinetics of3H-metoprolol, a new selective β1-receptor antagonist, have been studied in healthy volunteers by following the plasma concentrations and the urinary excretion of the unchanged compound and its total radioactive metabolites after oral and intravenous administration. The compound was rapidly and completely absorbed after oral administration, and about 40% of the dose reached the systemic circulation. The estimated half-life of the absorption process was 10 min. Metoprolol was extensively distributed to extravascular tissues, with the half-life of the distribution phase close to 12 min. About 95% of the dose was excreted in the urine within 72 hr, mainly in metabolized form. The elimination halflife of the compound was close to 3 hr as was also the half-life of the total metabolites after oral administration. After intravenous administration, the elimination half-life of the metabolites was raised to 5 hr, indicating that the route of administra tion might influence the metabolic pathways of the parent compound.

Key words

metoprolol β-receptor antagonist pharmacokinetics disposition 


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Copyright information

© Plenum Publishing Corporation 1974

Authors and Affiliations

  • Carl G. Regårdh
    • 1
  • Karl O. Borg
    • 1
  • Rustan Johansson
    • 2
  • Gillis Johnsson
    • 1
  • Lars Palmer
    • 1
  1. 1.Research Laboratories, AB Hässle, FackMölndal 1Sweden
  2. 2.Apoteket PilenLillhagen's HospitalHisings-Backa 3Sweden

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