A comparison of once and twice daily atenolol in hypertension.

The hypertensive action of atenolol has been studied in a randomized double-blind crossover comparison. Twelve patients showed a highly significant reduction in average supine systolic and diastolic blood pressures from pre-treatment values of 196.3/115.9 to 159.1/89.2 mmHg (26.1/15.4 kPa to 22.2/11.9 kPa) after 2 weeks on once daily atenolol. No dose-related reduction in blood pressure was seen and the single 100 mg daily dose was as effective as 100 mg twice daily or 50 mg twice daily. Blood pressures recorded after 2 weeks' atenolol were lower than those obtained at 7 days irrespective of dose.