Pharmacokinetic and pharmacodynamic properties of beta-blocking drugs influencing choice in treatment of systemic hypertension

Abstract

Diuretics and β blockers are the mainstay in treating mild and moderate systemic hypertension, but there is controversy as to which should be used first. Recent evidence of an increase in sudden death and a greater number of intolerable side effects in the diuretic-treated groups in the Multiple Risk Factor Intervention Trial in the U.S. and the Medical Research Council Trial in Great Britain has prompted some to suggest β blockers as first-line therapy. However, β blockers also have side effects, such as decreased ventricular function in patients with mild heart failure, increased airways resistance in those with chronic obstructive lung disease, increased plasma lipids, in particular low density lipoprotein cholesterol, and increased problems in patients with peripheral vascular disease and those with diabetes requiring insulin treatment. Many new β-blocking drugs with different pharmacokinetic and pharmacodynamic properties allow the physician to choose the best one for each patient. β-blocking drugs with long durations of action, high levels of bioavailability, β 1 selectivity and intrinsic sympathomimetic activity appear most suitable for therapy. Cardioselectivity is suggested for patients with obstructive lung disease and peripheral vascular disease, and diabetic patients who take insulin. Long durations of action permit infrequent administration and recently agents with intrinsic sympathomimetic activity have been shown to have less effects on plasma lipid levels. Acebutolol also reduces ventricular arrhythmias, and may therefore be used to reduce sudden death in patients with coronary artery disease. The pharmacokinetic and pharmacodynamic properties of β-blocking drugs can indicate the most appropriate choice for hypertensive patients. β 1-selective agents with intrinsic sympathomimetic activity and membrane stabilizing properties appear to be good choices for first-line therapy.