title: The effects of single-dose atenolol, labetalol, and propranolol on cardiac and vascular function.
abstract: The pharmacodynamic effects of single oral doses of atenolol (100 mg), labetalol (300 mg), and propranolol (80 mg) were compared with those of placebo in a randomized, double-blind, Latin square design in 12 patients with hypertension. Atenolol and propranolol both significantly reduced cardiac output (-0.55 vs. -0.31 L/min) and heart rate (-8.0 vs. -6.6 bpm), whereas labetalol had no effect on either parameter (-0.08 L/min; + 1.0 bpm). Labetalol significantly reduced vascular resistance (-339 dynes X cm/sec5), but atenolol and propranolol did not (147 vs. 62 dynes X cm/sec5). Only labetalol significantly reduced the systolic (-15.3 mm Hg), diastolic (-11.5 mm Hg), and mean blood pressures (-12.8 mm Hg). Atenolol significantly reduced only diastolic blood pressure (-5.20 mm Hg), whereas propranolol failed to lower these parameters significantly. These data indicate that the hemodynamic profile of labetalol differs from that of selective and nonselective beta-blockers. Labetalol lowered blood pressure primarily by reducing vascular resistance, whereas reductions in heart rate and cardiac output were the predominant effects of atenolol and propranolol.
mesh_terms: D000368:Aged; D001262:Atenolol / Q000097:blood / Q000627:therapeutic use*; D002302:Cardiac Output / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D007741:Labetalol / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000097:blood / Q000627:therapeutic use*; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D001262:Atenolol; D011433:Propranolol; D007741:Labetalol