Comparative Effects of Nebivolol and Metoprolol on Female Sexual Function

Beta-blockers (BB) are an important treatment for high blood pressure and heart disease. However beta-blockers can cause sexual dysfunction (SD) and this common side effect limits successful use of this class of medications. Sexual side effects often result in drug discontinuation, compromising therapy goals. The investigators are conducting the study to determine if nebivolol, a newer beta blocker that is selective for receptors in the heart and causes vasodilation in the body causes fewer sexual side effects, or even improves sexual function, compared with metoprolol succinate.

This protocol is designed to compare the effects two beta blockers, nebivolol (Bystolic) 5-10 mg daily with metoprolol succinate (Toprol XL) 100-200 mg daily on sexual function in post-menopausal women with high blood pressure. The study is composed of 2 treatment phases. At baseline subjects are randomized to either nebivolol 5 mg once daily or metoprolol succinate 100 mg once daily. After randomization, subjects are treated for 12 weeks with double blind therapy. Following double-blind therapy subjects enter a 2-week washout phase and are subsequently switched to the alternate therapy. After 4 weeks (visits 3 and 7) of double-blind treatment with either nebivolol 5 mg once daily or metoprolol succinate 100 mg once daily subjects will be evaluated and the need for dosage titration assessed. If blood pressure is not at goal the dosage of study medication will be doubled to nebivolol 10 mg once daily or metoprolol succinate 200 mg once daily. If blood pressure remains uncontrolled after 8 weeks of double blind treatment with study medication open label amlodipine 5 mg will be initiated (visits 4 and 8) at the discretion of the principal investigator. During double blind treatment subjects will be evaluated in clinic every 4 weeks. The primary efficacy variable is the change from baseline in Changes in Sexual Functioning Questionnaire (CSFQ) and the Female Sexual Function Index (FSFI). The primary study objective is to determine whether nebivolol causes fewer sexual side effects compared with metoprolol succinate and if nebivolol improves FSF in women. FSF will be assessed with the above questionnaires-FSFI and CSFQ.