--Disease Characteristics-- Orthostatic hypotension due to autonomic nervous system failure, i.e.: Fall in systolic blood pressure (supine to standing) of at least 15 mm Hg AND Symptoms of dizziness, lightheadedness, unsteadiness with a severity of 4.5 or less on a 10 point scale in 2 of 3 evaluations over a 3 day period --Prior/Concurrent Therapy-- No concurrent sympathomimetics or alpha-receptor agonists or antagonists No concurrent drug with significant smooth muscle relaxant or constrictive properties e.g., calcium channel blockers At least 30 days since other prior investigational agents --Patient Characteristics-- Hepatic: No coagulopathy Renal: No acute nephritis or chronic renal failure Cardiovascular: No sustained supine hypertension greater than 180/110 mm Hg No congestive heart failure No myocardial infarction within the last 6 months No uncontrolled arrhythmia (ventricular tachycardia or second or third degree heart block not treated with pacemaker) No unstable angina pectoris No history of cerebral vascular accident Other: No pheochromocytoma No thyrotoxicosis No seizure disorder Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception