Efficacy and tolerability of amlodipine camsylate/losartan 5/100-mg versus losartan/hydrochlorothiazide 100/12.5-mg fixed-dose combination in hypertensive patients nonresponsive to losartan 100-mg monotherapy

Abstract

Purpose: The aim of this study was to determine whether the efficacy and tolerability of amlodipine camsylate/losartan 5/100 mg/d (AML/LOS) are noninferior to those of losartan/hydrochlorothiazide 100/12.5 mg/d (LOS/HCTZ) fixed-dose combination in hypertensive patients unresponsive to losartan 100-mg/d monotherapy.

Methods: Male and female patients aged ≥ 18 years with hypertension despite 4-week, stable treatment with losartan 100-mg/d monotherapy were eligible for inclusion in this multicenter, randomized, double-blind study. Patients were randomly assigned to receive AML/LOS or LOS/HCTZ once daily for 8 weeks. The primary end point was the change from baseline to week 8 in sitting diastolic blood pressure (ΔsiDBP), and the secondary end points were the changes from baseline to 4 weeks in siDBP and sitting systolic BP (ΔsiSBP) and changes from baseline to 4 and 8 weeks in BP response rate. Tolerability was evaluated by physical examination, including vital sign measurement; laboratory analysis; and ECG.

Findings: Of 275 patients screened at 9 cardiovascular centers, 199 were enrolled (AML/LOS, n = 101; LOS/HCTZ, n = 98), and 183 completed the study. The demographic characteristics were similar between the 2 groups (mean age, 51.56 [9.97] years; men, 70.53%). At 8 weeks, the mean ΔsiDBP values were -11.54 (7.89) and -9.05 (6.57) mm Hg in the AML/LOS and LOS/HCTZ groups, respectively (both, P < 0.0001 vs baseline). The mean difference between the 2 groups was -2.57 mm Hg, a nonsignificant difference, meaning that AML/LOS was noninferior to LOS/HCTZ with regard to the primary end point. At 8 weeks, the mean uric acid level was changed significantly from baseline in the LOS/HCTZ group (+0.41 [0.80] mg/dL; P < 0.0001) but not in the AML/LOS group (-0.12 [0.82] mg/dL), representing a significant intergroup difference (P < 0.0001). Nineteen patients each in the AML/LOS (18.81%) and LOS/HCTZ (20.00%) groups experienced ≥ 1 adverse event, with 4 (3.96%) and 3 (3.16%) patients, respectively, experiencing 1 or more events considered by the investigators to have been treatment related.

Implications: The efficacy and tolerability of AML/LOS 5/100 mg/d was found to have been noninferior to those of LOS/HCTZ 100/12.5 mg/d in these hypertensive patients nonresponsive to losartan 100-mg/d monotherapy.

Keywords: amlodipine; hypertension; losartan.