and can be successfully used to prevent blood phobic vasovagal syncope. The palliative effect of water encompasses all OI including OH, postural tachycardia syndrome (POTS), and vasovagal syncope (VVS) Studies in adults have demonstrated that intake of water free of solute can increase blood pressure and improve sympathetic vasoconstriction after a sufficient time has elapsed for the water to reach the small intestine, say 20 minutes. Rapid water ingestion of approximately 16 ounces deserves special mention. Short-acting pressor drugs such as midodrine or drugs that enhance autonomic activity (atomoxetine, pyridostigmine) are alsoused. Defects in erythropoietin may occur as part of the denervation in autonomic failure. Supportive drug therapy often aims to increase blood volume by promoting salt and water retention (fludrocortisone) or by increasing red blood cell mass (recombinant erythropoietin). Such therapy would include physical countermaneuvers including compression garments, and dietary changes (increased salt, rapid water drinking). Supportive therapy focuses on decreasing symptomatic OH and syncope. It may also be the drug of choice for most neurogenic orthostatic hypotension (NOH) since it can provide norepinephrine production through alternative pathways. Thus, in the case of dopamine-beta-hydroxylase (DBH) deficiency, droxidopa, which bypasses the missing enzyme, can provide definitive remediation.

Supportive care and treatment of the underlying illness are essential.

Lennon Dutch Medicines Handbook