The Effect of Sildenafil Citrate (Viagra® (Registered Trademark)) on Brain Blood Flow in Multiple Sclerosis Patients

Healthy Controls and MS patients will be excluded if they have contraindications to MR scanning, such as the following:

1. aneurysm clip

2. implanted neural stimulator

3. implanted cardiac pacemaker or autodefibrillator

4. cochlear implant

5. ocular foreign body (e.g., metal shavings)

6. insulin pump

Healthy controls and MS patients will be excluded from this study if they have the following:

1. History of heart attack

2. History of treatment with nitrates for heart condition

3. History of carotid artery stenosis or evidence of greater than 50% carotid stenosis on screening MR angiogram

4. History of known vascular disease

5. History of stroke

6. History of migraine

7. Subjects who have a history of a reaction to MR contrast agents specifically gadopentetate dimeglumine will be excluded from participating in the contrast agent administration part of this protocol.

8. Healthy controls will be excluded if have history of alcohol or drug abuse.

9. Healthy controls will be excluded if Concurrent, clinically significant (as determined by the investigator) gastrointestinal, immunologic, pulmonary, neurologic, renal, and/or other major disease.

10. Healthy controls will be excluded if they have a previous known abnormality on Brain MRI examination.

11. Pregnant and lactating women will be excluded from the study.

12. Since certain drugs may interfere with the ability of the vessels in your brain to respond to Viagra, subjects taking steroids or sildenafil (within 24 hours) will be excluded from this study.

1. Pregnant and lactating women who are MS patients will be excluded from the study.

2. Diagnosis of primary progressive MS, defined as gradual progression of disability from the onset without relapses.

3. Concurrent, clinically significant (as determined by the investigator) immunologic, pulmonary, gastrointestinal, neurologic, renal, and/or other major disease in MS patients.

Treatment History in MS patients

If prior treatment with steroids was received, the subject must have been off treatment for the required period prior to enrollment (see below).

Agent: Corticosteroids

Time Required off Agent Prior to Enrollment: 8 weeks

Unwillingness or inability to comply with the requirements of this protocol including the presence of any condition (physical, mental, or social) that is likely to affect the subject's returning for follow-up visits to the NINDS, Neuroimmunology Clinic will be sufficient reason to exclude a subject.

The Effect of Sildenafil Citrate (Viagra® (Registered Trademark)) on Brain Blood Flow in Multiple Sclerosis Patients

What this study is about

The Effect of Sildenafil Citrate (Viagra® (Registered Trademark)) on Brain Blood Flow in Multiple Sclerosis Patients

What this study is about