Fainting is a loss of consciousness that happens quickly and sometimes without warning. A fainting episode usually resolves within seconds to minutes. If fainting is caused by another condition, then the condition will need to be treated.

In general, fainting is caused by decreased blood flow to the brain.

Blood Flow to the Brain
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Decreased blood flow to the brain can be caused by:

Most commonly, vasovagal spells. Vasovagal spells can occur:

  • During medical procedures
  • During times of high stress, trauma, or fright
  • After standing still for a long period of time

Medical conditions:

Fainting can also occur as a side effect to medications. These include:

  • Blood pressure medications
  • Medications to regulate heart rhythms
  • Diuretics
  • Certain antidepressants