Effect of metoprolol and pindolol monotherapy on plasma lipid- and lipoprotein-cholesterol levels (including the HDL subclasses) in mild hypertensive males and females.

Forty-five patients with mild hypertension were treated for 2 months with either metoprolol or pindolol in a randomized, blind, crossover study. The effects of metoprolol (100-300 mg/day) and pindolol (5-15 mg/day) on triglyceride (TG), cholesterol (C), high-density lipoprotein cholesterol (HDL-C), and HDL subfraction (HDL2-C and HDL3-C) levels were compared in males and females separately. Pindolol and metoprolol significantly elevated (10% above baseline level) the plasma TG level in both males and females. After metoprolol treatment, the HDL-C level remained unchanged in both sexes; however, a shift was found between HDL2-C and HDL3-C:HDL2-C decreased and a concomitant elevation in HDL3-C was observed. Pindolol significantly decreased total C, HDL-C, and HDL2-C levels in males. A similar trend (although the changes were not significant) was found in females. The results demonstrate the role of beta blockers in the inhibition of TG-rich lipoprotein elimination. These findings suggest that during long-term administration of metoprolol and pindolol, risks and benefits from beta-blocker therapy must be carefully considered. Continuous monitoring of lipid profiles is suggested during this treatment in order to avoid the potential worsening effect of beta blockers on risk factors of ischemic heart disease.