title: Vasovagal syncope: an update on the latest pharmacological therapies.
abstract: BACKGROUND
  Syncope is an abrupt loss of consciousness in response to reduced perfusion to the brain. Neurocardiogenic or vasovagal syncope results from a complex neurologic reflex, and treatments to prevent recurrence attempt to modulate aspects of that reflex.
  
  
  METHODS
  Pharmacologic treatments for vasovagal syncope address the syncope reflex in multiple ways. Fludrocortisone and sodium chloride increase systemic fluid volume. Midodrine, β blockers and norepinephrine transport inhibitors modulate the sympathetic nervous system. Other treatments for syncope modulate other neurotransmitters or affect heart rate. The most recent trials evaluating established and novel therapies are reviewed.
  
  
  CONCLUSIONS
  To reduce recurrence of vasovagal syncope, conservative measures are first line. If these fail to prevent recurrence, the most promising medical therapy includes midodrine. Randomized placebo-controlled data evaluating fludrocortisone, midodrine and β blockers in older patients are awaited. Because of the significance of the placebo effect in this condition, any treatment must be evaluated in a randomized double-blind placebo-controlled trial before being accepted as effective.
authors.affiliation: Mayo Clinic Arizona, Division of Cardiovascular Diseases , 5777 East Mayo Boulevard, Phoenix, AZ 85054 , USA.
authors.forename: John William
authors.initials: JW
authors.lastname: Schleifer
authors.forename: Win-Kuang
authors.initials: WK
authors.lastname: Shen
mesh_terms: D002986:Clinical Trials as Topic; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D018377:Neurotransmitter Agents / Q000378:metabolism; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D017410:Practice Guidelines as Topic; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D019462:Syncope, Vasovagal / Q000145:classification / Q000188:drug therapy* / Q000209:etiology; D014882:Water-Electrolyte Balance / Q000187:drug effects
chemical_list: D018377:Neurotransmitter Agents
keywords: autonomic; fludrocortisone; midodrine; neurocardiogenic; syncope; vasovagal; β blockers