Eleven centers in Tuscany, Italy, recruited 96 patients (aged 21-75 years) with mild-to-moderate essential hypertension [diastolic blood pressure (DBP) 95-115 mm Hg; systolic blood pressure (SBP) less than or equal to 200 mm Hg]. After a 4-week, single-blind, placebo run-in period, patients received lacidipine 4 mg once daily. If blood pressure was not controlled after 1 month (control = DBP less than or equal to 90 mm Hg, or less than or equal to 95 mm Hg if reduced by greater than or equal to 15 mm Hg from baseline), the dose was increased to lacidipine 8 mg once daily. Atenolol 50 mg once daily was added after 2 months' monotherapy, if required for blood pressure control. The study continued for 13 months. About 40% of patients were titrated to 8 mg lacidipine; only 7% required addition of atenolol. Lacidipine significantly reduced blood pressure, with 84% of patients showing control of pressure values 24 h after the previous dose on completion of 5 months' monotherapy (63% controlled with lacidipine 4 mg/day; 21% with lacidipine 8 mg/day). There was no clinically relevant difference in the first-dose effect between the two doses of lacidipine (4 mg and 8 mg); both smoothly reduced blood pressure, with maximum effect after 2 h. Lacidipine was well tolerated. Adverse events were those expected with dihydropyridines, were mainly mild and occurred early, disappearing without discontinuation of treatment. Results indicate that 4-8 mg of lacidipine, administered once daily, is effective and well tolerated in mildly to moderately hypertensive patients.