Antihypertensive effect of barnidipine 10 mg or amlodipine 5 to 10 mg once daily in treatment-naive patients with essential hypertension: A 24-week, randomized, open-label, pilot study

BACKGROUND: Dihydropyridine calcium antagonists are largely employed for the treatment of hypertension, coronary heart disease, and heart failure. OBJECTIVE: The aim of our study was to compare the antihypertensive effect of the dihydropyridine calcium antagonists barnidipine and amlodipine. METHODS: This was a 24-week, randomized, open-label, pilot study. Consecutive treatment-naive patients with grade I or II essential hypertension (office sitting systolic blood pressure [BP] of 140-179 mm Hg and diastolic BP of 90-109 mm Hg) were enrolled. The primary end points were the effect of treatment with either barnidipine 10 mg or amlodipine 5 mg once daily on office and ambulatory BP, left ventricular mass index (LVMI), and markers of cardiac damage, serum procollagen type I C-terminal propeptide, and plasma amino-terminal pro-B-type natriuretic peptide concentrations. Patients were assessed at enrollment, and 12 and 24 weeks. During each visit, the prevalence of adverse events (AEs) was also monitored using spontaneous reporting, patient interview, and physical examination, the relationship to study drug being determined by the investigators. Compliance with treatment was assessed at each study visit by counting returned tablets. RESULTS: Thirty eligible patients (20 men, 10 women; mean [SD] age, 47 [12] years) were included in the study; all patients completed the 24 weeks of study treatment. Twelve weeks after randomization, 6 patients in the amlodipine group had their dose doubled to 10 mg due to inadequate BP control. Mean BP reductions at study end were not significantly different between the barnidipine and amlodipine groups (office BP, -10.3/-9.4 vs -16.6/-9.1 mm Hg; ambulatory BP, 9.4/6.4 vs 8.1/5.1 mm Hg). Reductions in LVMI and markers of cardiac damage were not significantly different between the 2 groups. Significantly more patients in the amlodipine group reported drug-related AEs compared with those in the barnidipine group (9 [60%] vs 2 [13%]; P < 0.05). CONCLUSION: In this small sample of treatment-naive hypertensive patients, the antihypertensive effect of barnidipine 10 mg once daily was not significantly different from that of amlodipine 5 to 10 mg once daily.