Low Blood Pressure, All Causes

A blood pressure reading is made up of 2 numbers There is a top number over a bottom number. The top number is the systolic pressure. It measures your pressure as your heart is contracting (squeezing) to pump blood. The bottom number is the diastolic pressure. It measures your pressure when the heart is relaxing and refilling with blood. A normal blood pressure is a systolic pressure less than 120 and a diastolic pressure less than 80. Low blood pressure (hypotension) is a blood pressure that is less than what is normal for you. Low blood pressure can cause dizziness, lightheadedness, or fainting.

Some medicines can cause low blood pressure. They include:

  • High blood pressure pills

  • Water pills (diuretics)

  • Some heart medicines

  • Some antidepressants

  • Pain, anxiety, sedative, and sleeping medicines

Other causes include:

  • Dehydration, severe infection, or fever

  • Blood loss, such as bleeding from the stomach or intestines.

  • Heart failure

  • Change in heart rate or rhythm (arrhythmia)

  • A drop in blood pressure from a sudden change in body position, from lying down to standing (orthostatic hypotension)

  • Alcohol or drug intoxication

  • Neurological diseases that impair the autonomic nervous system (the portion of the nervous system that regulates such things as internal organs and blood vessels)

Treatment will depend on what is causing your low blood pressure.

Home care

Follow these guidelines when caring for yourself at home:

  • Rest until your symptoms get better.

  • Keep a record of your symptoms and what you were doing when they occurred. Bring the record with you to your next appointment.

  • Be aware of how quickly your blood pressure drops when you become dehydrated, spend a lot of time in the sun, or have low blood sugar. Take measures to prevent blood pressure drops at these times.

  • Follow the treatment plan described by your healthcare provider.

Follow-up care

Follow up with your healthcare provider, or as advised.

When to get medical advice

Call your healthcare provider right away if any of these occur:

  • Mild dizziness or lightheadedness

  • Small amount of black or red color, or blood, in your stools or vomit

  • Mild abdominal pain

  • Diarrhea or vomiting that doesn’t go away

  • You aren’t able to eat or drink

  • Fever of 100.4°F (38°C) or higher, or as advised by your provider

  • Burning feeling when you pee

  • Bad-smelling urine

Call 911

Call 911, or get immediate medical care at the nearest emergency department if any of the following occur:

  • Fainting or severe dizziness or lightheadedness

  • Large amount of black or red color, or blood, in your stools or vomit

  • Abnormal pain in chest, shoulder, arm, neck, or upper back

  • Abnormal shortness of breath or trouble breathing

  • Severe abdominal pain

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