Angiotensin converting enzyme inhibitors and angiotensin receptor blockers in hypertensive African Americans

Abstract

African-American hypertensives (AA) respond poorly to angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptors blockers (ARB) individually. This study investigates the effect of ACEI and ARBs individually and in combination, on diastolic blood pressure (DBP), plasma renin activity (PRA) and angiotensin II levels, in these patients. After baseline evaluation 44 AA patients, age 61.2±9.6 yrs, were randomized to ACEI enalapril (E) 10 mg (E4), increased to 20 mg (E8) after 4wks, or ARB candesartan (C) 16 mg (C4) increased to 32 mg (C8) after 4wks. After a total of 8wks of therapy, patients were crossed over to the other arm. Patients not responding to either of the two drugs were treated with a combination of both, starting with enalapril 10mg +candesartan 16 mg (CE4) for 4wks and then enalapril 20 mg+ candesartan 32mg (CE8) for 4 wks. At the end of each phase complete clinical and laboratory evaluation including chemistry, PRA AII levels, was done. At 4 8 wks DBP was significantly reduced with both E C. Non-responers (n=17) who received combination therapy with both E + C, showed only minimal additional fall in DBP. PRA increased only with C and CE at 4 8 wks. AII levels increased only with high dose E. All treatments decreased DBP significantlly but the magnitude of change was small. The relatively poor response of BP to ACEI and ARBs in AA may be related to inadequate blockade of angiotensin converting enzyme or AT1 receptor or rapid return of ATII level to baseline. Combination of ARB and ACEI did improve the response significantly. (See Table) p<0.01, p<0.05 p<0.01, p<0.05