Comparison of the efficacy and safety of fixed-dose amlodipine/losartan and losartan in hypertensive patients inadequately controlled with losartan: a randomized, double-blind, multicenter study

Abstract

BACKGROUND: Fixed-dose combination drugs may enhance blood pressure (BP) goal attainment through complementary effects and reduced side effects, which leads to better compliance. OBJECTIVE: This study aimed to evaluate the efficacy and safety profiles of once-daily combination amlodipine/losartan versus losartan. METHODS: This was an 8-week, double-blind, multicenter, randomized phase III study conducted in outpatient hospital clinics. Korean patients with essential hypertension inadequately controlled on losartan 100 mg were administered amlodipine/losartan 5 mg/100 mg combination versus losartan 100 mg. The main outcome measures were changes in sitting diastolic blood pressure (DBP) and sitting systolic blood pressure (SBP) and BP response rate from baseline values, which were assessed after 4 and 8 weeks of treatment. Safety and tolerability were also assessed. RESULTS: At week 8, both groups achieved significant reductions from baseline in DBP (11.7 ± 7.0 and 3.2 ± 7.9 mmHg), which was significantly greater in the amlodipine/losartan 5 mg/100 mg combination (n = 70) group (p < 0.0001). Additionally, the amlodipine/losartan 5 mg/100 mg combination group achieved significantly greater reductions in SBP at week 8 and in SBP and DBP at week 4 compared with the losartan 100 mg (n = 72) group (all p < 0.0001). Response rates were significantly higher in the amlodipine/losartan 5 mg/100 mg group versus the losartan 100 mg group (81.4% vs 63.9% at week 4, p < 0.0192; 90.0% vs 66.7% at week 8, p < 0.001). Both treatments were generally well tolerated. CONCLUSION: Switching to a fixed-dose combination therapy of amlodipine/losartan 5 mg/100 mg was associated with significantly greater reductions in BP and superior achievement of BP goals compared with a maintenance dose of losartan 100 mg in Korean patients with essential hypertension inadequately controlled on losartan 100 mg.