Differential effects of strict blood pressure lowering by losartan/hydrochlorothiazide combination therapy and high-dose amlodipine monotherapy on microalbuminuria: the ALPHABET study

We investigated the effects of losartan/hydrochlorothiazide (HCTZ) fixed combination therapy and high-dose amlodipine monotherapy on BP measurements and target organ protection. In this open-label multicenter trial, hypertensive patients were randomly allocated to receive losartan 50 mg or amlodipine 5 mg for 4 weeks, and the treatments were changed to combination of losartan 50 mg/HCTZ 12.5 mg or amlodipine 10 mg for a further 4 weeks. A total of 91 hypertensive patients (age 63.6 years), 47 in the losartan/HCTZ group and 44 in amlodipine group, were enrolled. After 8 weeks, the clinic BP, home BP, and 24-hour ambulatory BP were successfully controlled to the same level in both treatment groups (P < .001). Furthermore, both groups showed the same degree of BP reduction in the 24-hour, daytime, and nighttime (P < .001). B-type natriuretic peptide (BNP) also significantly decreased to the same level in both groups, whereas the reduction of urinary albumin/creatinine ratio (UACR) was greater in the losartan/HCTZ group than in the high-dose amlodipine group (–47.6% vs 2.4%, P < .001). Losartan/HCTZ combination and high-dose amlodipine have similar effects on clinic, home, and ambulatory BP control and BNP reduction, whereas losartan/HCTZ has superior effect on UACR reduction when compared with high-dose amlodipine.