Comparison of once daily atenolol, nitrendipine and their combination in mild to moderate essential hypertension.

1. The aim of the study was to compare the efficacy and the tolerability of treatment with atenolol (50-100 mg once daily), nitrendipine (20-40 mg once daily) and their combination (atenolol 50 mg + nitrendipine 20 mg) once daily in patients with mild to moderate essential hypertension. 2. The study was a randomised, double-blind, placebo controlled parallel groups design: blood pressures were measured at 'trough' effect (i.e. 24 h after dosing) to assess the adequacy of once-daily treatment. 3. Mean blood pressures (mm Hg) recorded on four occasions over 12 weeks of treatment were significantly lower both with atenolol (155/97 sitting: 155/104 standing) and with the combination of atenolol plus nitrendipine (153/96 sitting: 152/104 standing) than with placebo (169/108 sitting: 169/114 standing). Nitrendipine alone had no significant effect on blood pressure 24 h after dosing (165/104 sitting: 165/110 standing). 4. Withdrawals due to adverse effects were more common during treatment with nitrendipine: 7/32 of the patients experienced adverse effects attributable to intense systemic vasodilatation (e.g., flushing, erythema, headache). 2/37 patients taking atenolol were withdrawn: one because he developed a psoriatic rash and the other because of impaired peripheral circulation. Of the 35 patients taking combination treatment, two were withdrawn: one developed headaches and dyspnoea, and the other asthma. 5. The results suggest that once daily dosing with nitrendipine does not control blood pressure throughout the 24 h period in the majority of patients, and is associated with a considerable burden of adverse effects. Combination treatment was better tolerated but appeared to offer no advantages over atenolol alone in terms either of blood pressure control or adverse effects.