Abstract 633: Pharmacodynamic Interactions Between Nebivolol and Valsartan in Healthy Volunteers

Abstract

Background: Combining different classes of antihypertensive drugs is more effective for achieving blood pressure (BP) control than increasing the dose of monotherapies. An aim of this study was to investigate pharmacodynamic (PD) interactions between nebivolol, a β1 selective, vasodilatory beta blocker and valsartan, an angiotensin II type 1 receptor blocker. Methods: This was a single-center, randomized, open-label, multiple-dose, three-way crossover trial in 30 healthy adults aged 18-45 years. Participants were randomized into one of six treatment sequences (1:1:1:1:1:1) consisting of three 7-day treatment periods followed by a 7-day washout. Once-daily oral treatments comprised nebivolol 20 mg, valsartan 320 mg, or nebivolol 20 mg plus valsartan 320 mg. Outcomes included changes in BP, heart rate (HR), plasma angiotensin II, plasma renin activity (PRA), and 24-hour urinary aldosterone. Results: The drop in least square mean values of systolic and diastolic BP was significantly greater following the concomitant administration of nebivolol and valsartan than either monotherapy alone. The mean HR after treatment with nebivolol alone, as well as after the combined treatment, was consistently lower than valsartan monotherapy. A sharp increase in mean Day 7 PRA and plasma angiotensin II occurred in subjects receiving valsartan alone and this was significantly attenuated with concomitant nebivolol administration. Mean 24-hour urine aldosterone at Day 7 was substantially decreased after combined treatment, as compared to either monotherapy treatment. All treatments were safe and well tolerated. Conclusion: Nebivolol and valsartan co-administration led to greater reductions in BP compared to either monotherapy. Nebivolol attenuated valsartan-induced increases in angiotensin II levels and PRA and reduced urinary aldosterone levels. Hence, these mechanisms for BP lowering are complementary and provide a rationale for further investigation of this combination in patients with essential hypertension.