Improved efficacy of high-dose versus medium- and low-dose diltiazem therapy for chronic stable angina pectoris.

The efficacy of therapy with diltiazem, 360 mg/day, was studied in 11 men with chronic, stable angina pectoris. An initial dose-titration schedule in which diltiazem was increased weekly from placebo to 120, 240 and 360 mg/day (Period I) was followed by a randomized, double-blind, 1-month crossover trial of placebo vs diltiazem at 360 mg/day (Period II). A computer-assisted treadmill exercise test was performed at the end of each dose and each 2-week crossover period. Diltiazem at 360 mg/day, compared with placebo (Period II), significantly improved exercise performance. Exercise duration to onset of chest pain increased 40% from 5.3 +/- 2.1 to 7.4 +/- 2.7 minutes (p less than 0.01). Time to reach 1 mm of ST-segment depression increased 33%, from 5.1 +/- 2.0 to 6.8 +/- 1.8 minutes (p less than 0.01). Total exercise duration increased 16%, from 7.5 +/- 2.0 to 8.7 +/- 2.0 minutes (p less than 0.005). A computer-derived quantitative treadmill exercise score improved 27%, from -13.1 +/- 9.4 to -9.5 +/- 7.6 units (p less than 0.005), and the ST-segment depression at peak exercise improved from -1.9 +/- 1.1 to -1.6 +/- 1.2 mm (p less than 0.05). Progressive improvement in these variables was seen during the single-blind dose-titration period between 120 and 240 mg/day and between 240 and 360 mg/day (Period I). Baseline heart rate (HR) and diastolic blood pressure (BP) in the supine and upright position were significantly lower with diltiazem than with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

RCT Entities:   Population Interventions Outcomes