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Fainting during urination (micturition syncope): What causes it?

Medically reviewed by Last updated on Jul 16, 2022.

Micturition (or post-micturition) syncope is fainting while urinating or immediately after urinating. This is likely due to a severe drop in blood pressure. Micturition syncope is most common in older men and usually when getting up at night from a deep sleep.

The exact cause of micturition syncope isn't fully understood. But it may be related to a fall in blood pressure when you get up suddenly and stand at the toilet. Or this may happen when a full bladder empties very quickly. This is thought to cause a sudden drop in blood pressure.

Other factors that may play a role in micturition syncope include:

  • Alcohol
  • Hunger
  • Fatigue
  • Dehydration
  • Medical conditions, such as a respiratory infection
  • Use of alpha blockers to improve urination in men with prostate problems

Preventing micturition syncope

Micturition syncope isn't very common. It should be checked by a doctor because it may mean that there is an underlying medical condition. Prevention of micturition syncope depends on recognizing the factors that contribute to micturition syncope and avoiding them.

To avoid micturition syncope and a possible injury, you might suggest some of these strategies with your husband:

  • Avoid excessive alcohol
  • Don't get out of bed suddenly — first, sit on the edge of the bed and move your legs, making sure you aren't dizzy or lightheaded
  • Urinate sitting down
  • Ask your doctor whether any medications you're taking may be causing your condition

As much as possible, make sure that the floor from your bed to the bathroom is carpeted or padded. This can help prevent injury if you fall.

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