Once-daily nifedipine sustained release (nifelan) on forearm vascular resistance and regression of left ventricular hypertrophy in patients with mild to moderate essential hypertension

Background: Nifelan, a sustained-release formulation of nifedipine, is a new antihypertensive agent. However, its effect on peripheral vascular resistance and left ventricular mass is still controversial. Methods: We evaluated the antihypertensive efficacy and safety of nifelan in 20 patients with mild to moderate essential hypertension. After 2 weeks of a placebo- qualifying phase, the eligible patients were entered into an 8-week active treatment period in which nifelan was given 10-40 mg once-daily with gradual titration. Results: Seventeen patients (8 men, 9 women; age range 43-72 years, mean 52 years) completed the entire study. The mean sitting systolic and diastolic blood pressures were significantly reduced (p < 0.0001) by 13.8 mmHg and 9.6 mmHg, respectively, with a mean nifelan dose of 27.1 ± 2.7 mg per day, while the heart rate remained unchanged (75.9 ± 1.3 vs. 73.6 ± 0.9 beats pe minute, p = NS). Four patients (20%) reported side effects necessitating termination of nifelan treatment in 2 patients because of intolerance. One patient was found to be poorly compliant and withdrew prematurely from the study for unknown reasons without complaints of adverse effects. Echocardiographic left ventricular mass index was significantly reduced from 104.2 ± 4.6 g/m² to 96.6 ± 5.2 g/m² (p < 0.05), and the left ventricular diastolic function evaluated by E/A ratio showed a trend toward improvement from 0.97 ± 0.06 to 1.10 ± 0.07 (p = 0.06). Both forearm hemodynamic parameters showed favorable changes from baseline to the end of the study (forearm blood flow, 3.39 ± 0.28 vs. 4.04 ± 0.31 ml/100ml/min, p < 0.05; forearm vascular resistance, 37.75 ± 4.95 vs. 28.73 ± 3.34 mmgHg/ml/100ml/min, p < 0.05). The lipid profiles followed trends toward favorable changes after treatment (high density lipoprotein, 51.8 ± 3.0 vs. 54.4 ± 3.3 mg/dl, p = NS; low density lipoprotein, 146.1 ± 8.8 vs. 139. ± 10.6 mg/dl, p = NS). Hematological and biochemical parameters did not change at the end of treatment. Conclusion: Once-daily nifelan as monotherapy was safe and affective in Chinese patients with mild to moderate essential hypertension. Regression of left ventricular mass and reversal of unfavorable forearm hemodynamics were observed in these patients after short-term therapy.