Atomoxetine is a selective norepinephrine transporter inhibitor that increases the availability of norepinephrine in the synapse by blocking its reuptake. Our preliminary data in sixty-five patients with primary autonomic failure and neurogenic OH showed that atomoxetine was more effective than midodrine, standard of care, in improving standing SBP (+7.5 mm Hg). Notably, only atomoxetine and not midodrine induced a significant reduction in OH-related symptoms (lightheadedness and dizziness) compared with placebo. In this proposal, we will test the hypothesis that prolonged administration of the norepinephrine transporter blocker, atomoxetine, improves OH-related symptoms and OH-impact on daily activities compared with placebo in autonomic failure patients. We propose a randomized, double-blind, placebo-controlled, 2x2 crossover study.