Efficacy and safety of sustained-release diltiazem as replacement therapy for beta blockers and diuretics for stable angina pectoris and coexisting essential hypertension: A multicenter trial

To determine if a sustained-release form of the calcium entry blocker diltiazem would be a satisfactory substitute for the combination of β-adrenergic blocking agent and thiazide diuretic in the treatment of systemic hypertension and angina pectoris, 38 patients were studied in a 4-center trial. Blood pressure and heart rate were measured in the supine position, immediately after and 5 minutes after standing. Modified Bruce protocol treadmill tests were performed to determine the time to onset of 1 mm ST-segment depression, time to onset of chest pain and time to terminaton of exercise. Diltiazem monotherapy resulted in equivalent blood pressure control in 28 of 38 patients (74%). In the remaining patients, blood pressure control was achieved with resumption of the diuretic. Blood pressure with β blocker plus diuretic compared with diltiazem were, in the supine position 137 ± 22/82 ± 7 (± 1 standard deviation) versus 139 ± 22/82 ± 8 mm Hg, immediately after standing 131 ± 20/84 ± 9 versus 133 ± 21/82 ± 10 mm Hg and after standing for 5 minutes 134 ± 19/85 ± 8 versus 137 ± 18/85 ± 9 mm Hg (difference not significant for each). The heart rate with diltiazem was higher supine (67 ± 11 versus 60 ± 11 beats/min), standing (73 ± 13 versus 64 ± 14 beats/min) and 5 minutes after standing (73 ± 14 versus 63 ± 14 beats/min, p < 0.01 for each). With diltiazem, time to onset of 1 mm ST-segment depression increased from 402 ± 177 to 476 ± 178 seconds, time to chest pain increased from 441 ± 189 to 540 ± 210 seconds and total exercise time increased from 536 ± 153 to 608 ± 167 seconds (p < 0.01 for each). Replacement of combined β-adrenergic blocking agent and diuretic therapy with sustained-release diltiazem in the treatment of patients with both hypertension and angina will result in satisfactory blood pressure control with monotherapy in the majority of patients. It will also increase the duration of exercise required to produce evidence of myocardial ischemia.