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Safety and Efficacy of Intravenous Norepinephrine for Orthostatic Hypotension

Patients with chronic autonomic failure (CAF) often have disabling orthostatic hypotension (OH). OH in CAF patients is often associated with supine hypertension (hypertension while lying down), which can be severe. Drugs to treat OH worsen supine hypertension. Therefore, the combination of OH with supine hypertension poses a difficult therapeutic challenge. This protocol is a first step toward development of a way to maintain blood pressure during standing without worsening hypertension while lying down. The research question is will a drug (norepinephrine) given intravenously (IV) prevent blood pressure from falling in patients with orthostatic hypotension.

This is a placebo controlled, blinded study of 15 patients with neurogenic orthostatic hypotension. The study consists of two experimental days per participant. On a day before the day of norepinephrine (NE) infusion, the patient undergoes head-up tilting while blood pressure is monitored. Tilt angles are increased until the patient has orthostatic symptoms, systolic pressure decreases to less than 90 mm Hg, or systolic pressure decreases by more than 80 mm Hg. On the day of NE infusion patients, receive NE and placebo with the sequence of treatments randomized. If the patient has severe supine hypertension (more than 200 mm Hg systolic), then NE is infused beginning with the patient at whatever tilt angle is required for baseline pressure to be less than 200 mm Hg. NE is infused at doses titrated to keep directly recorded systolic blood pressure at or above the baseline value during exposure to higher tilt angles. When placebo is given, angles of tilt are increased until the patient has orthostatic symptoms, systolic pressure decreases to less than 90 mm Hg, or systolic pressure decreases by more than 80 mm Hg.