Abstract
Combining different classes of antihypertensives is more effective for reducing blood pressure (BP) than increasing the dose of monotherapies. The aims of this phase I study were to investigate pharmacokinetic and pharmacodynamic interactions between nebivolol, a vasodilatory β1-selective blocker, and valsartan, an angiotensin II receptor blocker, and to assess safety and tolerability of the combination. This was a single-center, randomized, open-label, multiple-dose, 3-way crossover trial in 30 healthy adults aged 18-45 years. Participants were randomized into 1 of 6 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), and nebivolol-valsartan combination (20/320 mg). Outcomes included AUC0-τ,ss, Cmax,ss, Tmax,ss, changes in BP, pulse rate, plasma angiotensin II, plasma renin activity, 24-hour urinary aldosterone, and adverse events. Steady-state pharmacokinetic interactions were observed but deemed not clinically significant. Systolic and diastolic BP reduction was significantly greater with nebivolol-valsartan combination than with either monotherapy. The mean pulse rate associated with nebivolol and nebivolol-valsartan treatments was consistently lower than that associated with valsartan monotherapy. A sharp increase in mean day 7 plasma renin activity and plasma angiotensin II that occurred in valsartan-treated participants was significantly attenuated with concomitant nebivolol administration. Mean 24-hour urine aldosterone at day 7 was substantially decreased after combined treatment, as compared with either monotherapy. All treatments were safe and well tolerated. In conclusion, nebivolol and valsartan coadministration led to greater reductions in BP compared with either monotherapy; nebivolol and valsartan lower BP through complementary mechanisms.