At a glance
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A Pilot Study to Detect the Effect of Sildenafil Citrate on Cerebral Blood Perfusion in Multiple Sclerosis Patients by Perfusion MRI
In Brief
An observational study for Multiple Sclerosis. Completed, across 1 site.
Detailed Summary
This study will determine whether sildenafil citrate, commonly known as Viagra, can cause increased blood flow to the brain in a wide range of multiple sclerosis (MS) patients, including women. Although people with MS can have reduced blood flow in the brain as part of the disease process, it has been observed that men with MS may have increased blood flow to the brain while taking sildenafil citrate. This study will measure brain blood flow or blood volume in men and women with MS before and after taking Viagra and compare the results to those in healthy volunteers in an effort to better understand the disease. Healthy volunteers 18 years of age and older and patients with MS between 18 and 55 years of age may be eligible for this study. Volunteers are screened with a medical history and physical examination, and patients with MS are evaluated with a complete neurological examination and screening for heart disease, including history of chest pain, heart attack, and use of nitrates. Participants undergo magnetic resonance imaging (MRI) before and after taking Viagra. During the scanning, subjects lie still on a table that can slide in and out of the cylindrical metal scanner. Scanning time varies from 20 minutes to 3 hours, with most scans lasting between 45 and 90 minutes. First, a scan is obtained of the carotid arteries (major arteries in the neck supplying blood to the brain) to determine if the arteries are narrowed, and then baseline MRI scans and measures of brain blood flow are obtained. The subject then comes out of the scanner and takes a Viagra pill. After 1 hour, the subject returns to the scanner and more scans are obtained to determine changes in brain blood flow and blood volume following Viagra. A catheter (thin plastic tube) is placed in the subject's arm before he or she enters the magnet for the second time for injection of a contrast agent called gadolinium DTPA, which allows brain structures to be distinguished more clearly.