The Effect of Metoprolol and Atenolol on Plasma High Density Lipoprotein Levels in Man

The effects of two beta-adrenoreceptor blocking drugs, metoprolol and atenolol, on plasma lipoproteins were studied in thirty-four patients using a single-blind cross-over design, with a 10-day placebo washout period between drugs. 2. Compared with placebo values, neither metoprolol nor atenolol influenced total plasma cholesterol levels, while total plasma triglycerides increased slightly. 3. Low density lipoprotein protein level remained unaltered, while high density lipoprotein (HDL) cholesterol and protein were significantly reduced by both beta-adrenoreceptor blockers. 4. The ratio of total cholesterol to HDL cholesterol was increased by both drugs. 5. The data suggest that patients taking these drugs over many years may be exposing themselves to increased vascular risk, despite other anticipated benefits from such therapy.