Blood Pressure Effects of High-Dose Amlodipine-Benazepril Combination in Black and White Hypertensive Patients Not Controlled on Monotherapy

BACKGROUND: Black hypertensive patients are more resistant to angiotensin-converting enzyme (ACE) inhibitor monotherapy than White patients. This resistance can be overcome with the combination of ACE inhibitors with diuretics or calcium-channel blockers (CCBs). OBJECTIVES: The objective of this clinical investigation was to evaluate the antihypertensive effectiveness of monotherapy with the ACE inhibitor benazepril or the CCB amlodipine and their combination in Black and White hypertensive patients in two separate studies. METHODS: This was a post hoc analysis of data from two separate studies, pooled because of their similarities, to increase the sample size. Outpatient Black and White hypertensive patients were selected for these studies. In study H2303, 201 patients of both sexes and races, whose mean seated diastolic blood pressure (MSDBP) was ≥95 mmHg after 4 weeks of single-blind treatment with benazepril 40mg/day, were randomized into two groups. Group 1 received benazepril 40mg/day and group 2 received amlodipine/benazepril 5/40mg/day, which was uptitrated to amlodipine/benazepril 10/40 mg/day at week 4 of the study. In study H2304, 812 similar patients, whose MSDBP was ≥95 mmHg after 4 weeks of single-blind treatment with amlodipine 10 mg/day, were randomized into three groups. Group 1 received amlodipine/benazepril 10/20 mg/day, uptitrated to amlodipine/benazepril 10/40 mg/day after 2 weeks. Group 2 received amlodipine/benazepril 10/20 mg/day. Group 3 received amlodipine 10 mg/day. All three groups were followed up for 6 additional weeks. RESULTS: This report presents the results of post hoc analysis of pooled data from two separate but similar studies. Combination therapy resulted in greater lowering of MSDBP and mean seated systolic blood pressure (MSSBP) than monotherapy with either benazepril or amlodipine (p< 0.001). With respect to combination therapy, the combination of amlodipine/benazepril 10/20 mg/day resulted in greater blood pressure (BP) reductions in White patients than in Black patients (p<0.004). In contrast, the combination of amlodipine/benazepril 10/40 mg/day resulted in similar BP reductions in both Black and White hypertensive patients. There were no serious clinical or metabolic side effects noted, with the exception of pedal edema, which was more common with amlodipine monotherapy. CONCLUSION: This study showed that combination therapy with amlodipine/benazepril is more effective in BP lowering than monotherapy with the component drugs. Black hypertensive patients are responsive to the combination of amlodipine/benazepril; however, they require higher dose combinations for BP reductions similar to those achieved in White hypertensive patients.