Effectiveness of barnidipine 10 or 20 mg plus losartan 50-mg combination versus losartan 100-mg monotherapy in patients with essential hypertension not controlled by losartan 50-mg monotherapy: A 12-week, multicenter, randomized, open-label, parallel-group study.

BACKGROUND

Increasing the dose or adding a second antihypertensive agent are 2 possible therapeutic choices when blood pressure (BP) is poorly controlled with monotherapy.

OBJECTIVE

This study investigated the effectiveness and tolerability of barnidipine 10 or 20 mg added to losartan 50 mg versus losartan 100 mg alone in patients with mild to moderate essential hypertension whose BP was uncontrolled by losartan 50-mg monotherapy.

METHODS

This was a 12-week, multicenter, randomized, open-label, parallel-group study. Eligible patients (aged 30-74 years) had uncontrolled hypertension, defined as office sitting diastolic BP (DBP) > or =90 mm Hg and/or systolic BP (SBP) > or =140 mm Hg, and mean daytime DBP > or =85 mm Hg and/or SBP > or =135 mm Hg. All were being treated with losartan 50 mg at enrollment. After a 1-week run-in period while taking losartan 50 mg, patients were randomly assigned to 6 weeks of treatment with open-label barnidipine 10 mg plus losartan 50 mg or losartan 100-mg monotherapy. At the end of this period, patients with uncontrolled BP had barnidipine doubled to 20 mg and continued for an additional 6 weeks, whereas patients not achieving control on treatment with losartan 100 mg were discontinued. Office BP was measured at each visit, whereas 24-hour ambulatory BP monitoring (ABPM) was performed at randomization and at the final visit (ie, after 12 weeks of treatment, or at 6 weeks for patients not controlled on losartan 100 mg). The intent-to-treat population included all randomized patients who received at least one dose of study treatment and had valid ABPM recordings at baseline and the final visit. The primary end point was the change in daytime DBP between baseline and 12 weeks of treatment, compared between the combination treatment and monotherapy. Adverse events (AEs) were evaluated during each study visit.

RESULTS

A total of 93 patients were enrolled (age range, 30-75 years; 60% [56/93] men). After the 1-week run-in period, 68 patients were randomly assigned to 6 weeks of treatment with open-label barnidipine 10 mg plus losartan 50 mg (n = 34) or losartan 100-mg monotherapy (n = 34). A total of 53 patients were evaluable (barnidipine plus losartan, n = 28; losartan, n = 25). After 6 weeks of treatment, 18 patients in the combination treatment group (64.3%) had their dose of barnidipine doubled from 10 to 20 mg because BP was not normalized by treatment, whereas 8 patients in the losartan group (32.0%) were discontinued for the same reason. The between-treatment difference (losartan alone - combination treatment) for changes from baseline in daytime DBP was -1.7 mm Hg (95% CI, -5.8 to 2.4 mm Hg; P = NS). A similar result was observed for daytime SBP (-3.2 mm Hg; 95% CI, -8.1 to 1.7 mm Hg; P = NS). Likewise, no significant differences were found for nighttime values (mean [95% CI] DBP, 0.5 mm Hg [-3.7 to 4.7 mm Hg]; SBP, 1.5 mm Hg [-4.1 to 7.1 mm Hg]) or 24-hour values (DBP, -0.9 mm Hg [-4.8 to 2.9 mm Hg]; SBP, -1.6 mm Hg [-5.9 to 2.7 mm Hg]). Combination treatment was associated with a significantly higher rate of SBP responder patients (ie, <140 mm Hg or a reduction of > or =20 mm Hg) compared with monotherapy (82.1% [23/28] vs 56.0% [14/25]; P = 0.044). Drug-related AEs were reported in 4 patients taking combination treatment (total of 7 AEs, including 2 cases of peripheral edema and 1 each of tachycardia, atrial flutter, tinnitus, confusion, and polyuria) and in 2 patients taking losartan alone (total of 2 AEs, both tachycardia).

CONCLUSIONS

This open-label, parallel-group study found that there was no significant difference in the BP-lowering effect of barnidipine 10 or 20 mg in combination with losartan 50 mg compared with losartan 100-mg monotherapy in these patients with essential hypertension previously uncontrolled by losartan 50-mg monotherapy. However, the percentage of responders for SBP was significantly higher with the combination. Both treatments were generally well tolerated. European Union Drug Regulating Authorities Clinical Trials (EudraCT) no. 2006-001469-41.