[Comparative effects of losartan and amlodipine on activities of sympathetic nerve, renin-angiotensin-aldosterone system and brain natriuretic peptide in the elderly hypertensive patients].

This study investigated the comparative effects of losartan and amlodipine on the activation of the sympathetic nervous system, renin-angiotensin-aldosterone system (R-A-A system) and brain natriuretic peptide (BNP) in patients with essential hypertension. Twenty-four elderly patients who had received more than 12 months of antihypertensive treatment with amlodipine participated in this study. The treatment regimen of 5 mg/day amlodipine was changed to 50 mg/day losartan. Plasma catecholamines (norepinephrine, epinephrine and dopamine), active renin, aldosterone and BNP concentration were measured before and after an average of 5 months of losartan treatment. After losartan treatment, blood pressures were not changed, suggesting the comparable effect of 50 mg losartan and 5 mg amlodipine on elevated blood pressure. Losartan significantly reduced norepinephrine (799 +/- 277 pg/mL vs. 692 +/- 268 pg/mL, p < 0.05) and aldosterone concentration (81.2 +/- 35.3 pg/mL vs. 55.2 +/- 17.7 pg/mL, p < 0.01), whereas there were not any changes in BNP concentrations. These findings suggested that losartan might be superior to amlodipine in prevention of chronic or intermittent sympathetic hyperactivity and enhanced R-A-A system.