Chronic Orthostatic Hypotension
Synthesis of norepinephrine from L-DOPS
One of the most disabling symptoms of patients with autonomic failure is orthostatic hypotension. In patients with orthostatic hypotension, blood pressure falls when changing from a lying or sitting position to a standing one. Because blood pressure falls, not enough blood reaches the brain, causing dizziness, lightheadedness, unsteadiness, dimming of vision, generalized weakness and sometimes loss of consciousness (i.e., syncope).
Orthostatic hypotension in autonomic failure occurs because the release of norepinephrine, the neurotransmitter used by autonomic nerves to send signals to the blood vessels and the heart, is deficient. L-DOPS is an orally active synthetic precursor of norepinephrine.
This clinical trial will determine how effective is L-DOPS in treating orthostatic hypotension. Patients in the trial are admitted to the Clinical Research Center at The Mount Sinai Hospital for 7 to 14 days. The study is supported in part by the National Institute of Health (NIH), National Organization for Rare Disorders (NORD), and the International Federation of Parkinson's Disease Foundation, Inc.
[GCO # 98-243 (2)]
All protocols are approved by the Institutional Review Board of The Mount Sinai Medical Center.
Regular fainting spells, also called vasovagal or neurally mediated syncope, are caused by a sudden fall in blood pressure and slowing of the heart that temporarily impairs the blood supply to the brain.
Male erectile dysfunction is frequent in patients with autonomic failure. Sildenafil (Viagra®) is useful in treating male erectile dysfunction. The effect of this drug on blood pressure in patients with autonomic failure is not fully known. This clinical trial will determine whether Sildenafil affects blood pressure in patients with primary autonomic failure. Patients in the trial will be admitted to the Clinical Research Center at The Mount Sinai Hospital for 48 hours. This study is supported in part by the NIH and by Pfizer.
