Metabolic parameters: how important are pharmacologically-induced changes?

It has been suggested that beta-blockers do not significantly reduce the frequency of coronary disease in hypertensives because they adversely affect the plasma lipoprotein profile. Non-selective beta-blockers cause a significant elevation of triglycerides and a reduction in the level of high-density lipoprotein. Cardioselective beta-blockers have similar, but less marked, effects. The non-selective beta-blockers with intrinsic sympathomimetic activity have little effect on the lipid profile, yet these are the least effective in reducing coronary mortality after myocardial infarction. Elevated blood flow velocity and high catecholamine levels can damage the vascular endothelium. This leads to increased permeability and the deposition of lipids. Beta-blockers reduce peak blood velocity and decrease the activity of catecholamines in plasma, which should reduce endothelial damage and the subsequent formation of plaques. Studies in animals have indeed shown that beta-blockers reduce the level of atherosclerosis, despite an elevation of serum lipids.