The relationship between age and the antihypertensive efficacy of calcium antagonists has been investigated by different authors with conflicting results. In order to evaluate this relationship an Italian multicentre study investigated 2184 patients with mild to moderate hypertension with an age range of 24-90 years. Initial treatment consisted of nicardipine monotherapy (daily dose 40-80 mg/day in two or three oral administrations); after 4 weeks other antihypertensive agents could be added in non-responders (seated blood pressure greater than 160/95 mmHg). The patients were divided into four groups according to age (less than or equal to 55 years, 56-65 years, 66-75 years and greater than 75 years). Nicardipine-based treatment reduced systolic and diastolic blood pressures to similar levels independently of the age of the patients. The correlation between systolic blood pressure reduction and age was only 0.141 (NS). The percentage of patients treated with nicardipine monotherapy was similar in all age groups, but the incidence of side effects, mostly transient and mild, was lower in older than in younger patients. In patients older than 65 years with isolated systolic hypertension (systolic pressure greater than 160 and diastolic pressure less than 90 mmHg), nicardipine-based therapy significantly lowered systolic blood pressure only from 180 +/- 11/87 +/- 6 to 148 +/- 14/84 +/- 8 mmHg.