In this study we used casual and 24-h blood pressure (BP) monitoring and Doppler echocardiographic data to investigate the antihypertensive and hemodynamic effects of isradipine 5 mg in the new slow-release oral (SRO) formulation administered once daily for 12 weeks to 10 patients with mild to moderate hypertension. The antihypertensive action of SR isradipine was revealed by the normalized values of casual BP in 60 patients and by the significant reduction of 24-h BP variability as assessed by mean standard variation, coefficient of variation and the percent incidence of abnormal levels of both systolic and diastolic BP during 24 h (p less than .001). The echocardiographic data showed some beneficial hemodynamic effects (improvement of systolic and diastolic indices) without significant variation of left ventricular structure. The drug was well tolerated, with a low incidence of side effects. In conclusion, SR isradipine can be considered a safe and effective first-choice drug for the treatment of mild to moderate hypertension.