Differential Effects of Amlodipine on Ambulatory Blood Pressure in Elderly Hypertensive Patients With Different Nocturnal Reductions in Blood Pressure

Previous studies have discovered that amlodipine given once daily can reduce blood pressure (BP) throughout the day and night. The effects of amlodipine on day and night BP have not been fully investigated in groups of hypertensives with different diurnal variations. In a prospective study, we performed 24-h ambulatory BP monitoring before and after once-daily use of amlodipine in three groups of asymptomatic elderly hypertensive patients with different nocturnal BP reductions, as follows: 10 extreme dippers with nocturnal reduction of systolic BP > or = 20% of daytime systolic BP, 17 dippers (reduction by > or = 10% to 10 mm Hg was observed when the baseline systolic/diastolic BP was < 120/70 mm Hg. Multiple linear regression analysis disclosed that the nighttime BP reduction afforded by amlodipine was dependent on the baseline nighttime BP levels, but not on the baseline nocturnal fall of BP. Once-daily use of amlodipine reduced BP levels throughout the day and night in hypertensive patients who show minimal or mild nocturnal BP fall, but it had no effects on nocturnal BP in those who show a substantial nighttime BP reduction. Thus, when we controlled using daytime office BP, amlodipine might not further reduce nocturnal BP to the extent that it accelerates the brain ischemia in some hypertensive patients with marked nocturnal BP reduction.