title: Maximal exercise power after a single dose of metoprolol and of slow-release metoprolol.
abstract: The treatment of hypertension with a single daily-dose of a beta-blocker gives rise to high peak-plasma concentrations 1.5 h after ingestion. After slow release-preparations of beta-blockers, the peak concentrations are half those produced by the conventional preparation at the same oral dose. A frequently occurring side-effect of beta-blocker therapy is fatigue. In this study the effect of a single dose of metoprolol 300 mg, 200 mg, 200 mg slow-release and a placebo on maximal exercise power was tested in 6 healthy subjects, 1.5 h and 24 h after ingestion. Maximal exercise power was significantly reduced 1.5 h after ingestion of metoprolol 300 mg and 200 mg. No change was found 1.5 h after 200 mg of a slow-release preparation. The possible reasons for reduced maximal exercise power are discussed. It is concluded that use of a beta-blocker for the treatment of hypertension in a single daily-dose regimen may be a reason to prefer a slow-release preparation.
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D003692:Delayed-Action Preparations; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D005082:Physical Exertion; D011412:Propanolamines / Q000494:pharmacology*
chemical_list: D003692:Delayed-Action Preparations; D011412:Propanolamines; D008790:Metoprolol