The relevance of intrinsic sympathomimetic activity for beta-blocker-induced changes in plasma lipids.

The possible relevance of intrinsic sympathomimetic activity (ISA) for beta-blocker-induced changes in plasma lipids was investigated by reviewing the literature and analyzing the results separately for nonselective beta-blockers, beta 1-selective beta-blockers, and those possessing ISA. It was confirmed that with the exception of the nonselective beta-blocker sotalol, beta-blocker therapy has little influence on the plasma concentrations of total cholesterol and low-density lipoprotein (LDL)-cholesterol. The small differences in mean changes in LDL-cholesterol observed among the three groups of beta-blockers are probably of negligible practical importance. More important differences emerged from the pooling of data on plasma triglycerides and high-density lipoprotein (HDL)-cholesterol. Here, beta-blockers possessing ISA showed the smallest mean increase in triglycerides and an increase in HDL-cholesterol, which compared favorably with the decrease found for nonselective and beta 1-selective beta-blockers. Of the individual beta-blockers, pindolol exhibited the most favorable lipid profile. A close inverse correlation was found between the changes in triglycerides and HDL-cholesterol in the various studies. This finding, together with other arguments, supports the view that these changes are the result of inhibition of lipoprotein lipase by adrenergic mechanisms.