Orthostatic hypotension is a condition of abnormal blood pressure regulation upon standing. The blood pressure quickly decreases, more than 20/10 mm Hg, when rising from a lying down or sitting position to a standing position.

Measuring of Blood Pressure
Placement of Blood Pressure Cuff
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Orthostatic hypotension has several causes.

  • Hypovolemia is the most common cause. It may be due to:
    • Excessive use of loop diuretic medications
    • Vasodilator medications, such as nitrate preparations, calcium channel blockers, or ACE inhibitors
    • Dehydration
    • Prolonged bedrest
    • Addison’s disease with inadequate salt intake
  • Impaired autonomic (nerve) reflex due to certain diseases:
  • Decreased heart muscle contractility or vascular responsiveness
  • Certain drugs:
    • Monoamine oxidase (MAO) inhibitors
    • Tricyclic antidepressants
    • Tetracyclic antidepressants
  • Phenothiazine antipsychotic drugs, such as chlorpromazine, promazine, thioridazine
  • Atypical antipsychotics
  • Quinidine
  • Levodopa
  • Barbiturates
  • Alcohol