Antihypertensive drug therapy uniformity of efficacy was evaluated in a group of elderly hypertensive subjects with trough-to-peak ratio, after a period of antihypertensive drug therapy with ACE-inhibitor fosinopril. An ambulatory blood pressure monitoring (ABPM) with evaluation of blood pressure variability assessed by standard deviation (S.D.) and coefficient of variation (C.V.) were evaluated in each subjects. Our preliminary data showed that the treatment with fosinopril had satisfactory uniformity of efficacy during all the 24-hour period, with both full dose (20 mg) and reduced dose (10 mg); little influence on blood pressure variability was determined by antihypertensive treatment.