To investigate the efficacy and tolerability of lercanidipine, used as monotherapy once a day, in elderly patients with isolated systolic hypertension (ISH), 83 patients were enrolled in this multicenter, double-blind, randomized, placebo-controlled study. All patients were older than 60 years, and their mean age was 66.7 +/- 5.4 years. ISH was defined as SBP > or = 160 mmHg, and DBP < 95 mmHg. After wash-out and placebo run-in periods, patients were randomly assigned to placebo or lercanidipine (10 mg once a day) treatment for 4 weeks. Non-responding patients of the lercanidipine-treated group were later treated with 20 mg of lercanidipine once a day for 4 additional weeks. At the end of the study, the reduction in systolic blood pressure was significantly larger in the lercanidipine-treated patients (-32.4 mmHg) compared to the fall observed in the placebo group (-9.6 mmHg). Diastolic blood pressure decreased slightly but significantly in the lercanidipine-treated patients only. At the end of lercanidipine treatment, 23 of 37 patients (62%) were normalized. Changes in heart rate, occurrence of orthostatic hypotension, and clinically relevant changes in electrocardiographic and laboratory findings were not observed in either group. Lercanidipine treatment was suspended in one patient because of epigastric pain. These data indicate that lercanidipine, used as monotherapy once a day, is effective in lowering elevated systolic blood pressure in elderly patients, and is well tolerated.