A number of studies have shown the benefit of hypertensive treatment even though the most common forms of the disease are mild-to-moderate in severity. Considering the overall aging of the world's population, it is of particular interest to study hypertension and its treatment in geriatric patients. A short-term study of isradipine was conducted to assess its effectiveness and tolerability in patients with mild-to-moderate hypertension. The study was carried out by general practitioners and involved 3343 patients, aged > or = 18 years, with diastolic blood pressures (DBPs) ranging from 95 to 114 mm Hg. A 4-week wash-out and placebo run-in phase was followed by a 12-week active treatment period with isradipine at 1.25 or 2.5 mg/day, depending on the blood pressure response. Posttreatment results in a subgroup of 1092 patients (444 men and 648 women), aged > or = 60 years, showed decreases in systolic blood pressure (SBP) from 173.1 to 149.2 mm Hg (mean decrease, 20.9 mm Hg) and, in DBP, from 102.0 to 85.0 mm Hg (mean decrease, 16.9 mm Hg). The majority (84.6%) of these patients showed DBP reductions of > 10 mm Hg, and 82.3% achieved normalization (DBP < 90 mm Hg) at the end of treatment. The mean dosage was 1.74 +/- 0.69 mg twice daily, and 37% of patients doubled their initial 1.25 mg twice daily dosages. There were no significant changes in either heart rate or major metabolic parameters. Adverse events were reported by 3.1% of the patients, and 90% of both patients and physicians expressed satisfaction with the therapy. There were no differences between men and women with regard to adverse events or efficacy, nor were the results in patients > or = 60 years different from those in younger patients. Thus, isradipine was effective and well tolerated in these geriatric patients.