Use of Sildenafil for Treatment of Urinary Incontinence

The investigators goal is to develop medical treatments for stress/mixed urinary incontinence. Sildenafil has been shown to improve blood flow as well as muscle mass and strength and to decrease muscle fatigue. The investigators believe that it will improve muscular atrophy in the pelvic floor, thus improving symptoms of urinary incontinence related to pelvic floor dysfunction.

Inclusion Criteria: * Postmenopausal females, 50-80 years of age, at the time of consent * Have stress or mixed urinary incontinence, with at least 3 episodes/week * Willing and able to comply with study procedures * Willing and able to provide written informed consent Exclusion Criteria: * Significant heart, liver, kidney, pulmonary, blood, autoimmune or peripheral vascular disease (history of Hashimoto's thyroiditis is not exclusionary if stable and thyroid replacement is being administered. Thyroid testing will be performed at screening and as needed during study visits. ) * Systolic blood pressure \150, diastolic blood pressure \90 after repeated evaluation with proper cuff. This range is smaller than the acceptable range stated in the prescribing information for sildenafil (\>90/50 and \ 40 * HIV, Hepatitis B, or Hepatitis C * Use of systemic nitrates, anabolic steroids or corticosteroids in the past 6 months * Use of alpha blockers * Any medical condition that, in the opinion of the investigator, would place the subject at increased risk for participation. * Known allergic reaction to any agent under investigation or required by the protocol. * History of prior non-compliance or the presence or history of psychiatric condition (including drug or alcohol addiction) that would, in the opinion of the investigator, make it difficult for the subject to comply with the study procedures or follow the investigators instructions. * Females who are pregnant or lactating.