Atenolol v placebo in mild hypertension: renal metabolic and stress antipressor effects.

The effects of 8 week treatment periods of atenolol and placebo on effective renal plasma flow (ERPF), glomerular filtration rate (GFR), plasma renin activity (PRA), oral glucose, fasting lipids and Achilles tendon reflex were compared in a double-blind crossover trial in ten subjects with mild hypertension. 2 Atenolol reduced resting blood pressure and pulse rate but did not prevent the rise in blood pressure and pulse rate in response to three kinds of stress. 3 Mean glomerular filtration rate and effective renal plasma flow were below the normal range during placebo (1.31 ml/s and 7.40 ml/s respectively) but were not significantly different on atenolol (1.23 ml/s and 7.18 ml/s). Serum urea was significantly (P < 0.01) higher on atenolol (6.7 mmol/l) than on placebo (5.6 mmol/l) but serum creatinine did not change. PRA was lower on atenolol (0.42 nmol 1-1 h-') than on placebo (1.01 nmol 1-' h'-). 4 The mean values of fasting cholesterol, triglycerides, ankle jerk contraction time, spirometry, weight, serum potassium, sodium and chloride were similar on atenolol and placebo. 5 Fasting blood sugar was a little higher (P < 0.05) on atenolol and the 1 and 2 h post-glucose serum insulin levels were a little lower (P < 0.01). 6 The cardioselectivity of atenolol does not impair its anti-hypertensive effect and may be associated with less effect on renal function. The metabolic effects of atenolol seem to differ from those of metoprolol.