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Definition

Low Blood Pressure, All Causes

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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 (sepsis), 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 or postural hypotension).

  • Alcohol or drug intoxication.

  • Neurological diseases that impair the autonomic nervous system. This is the part of the nervous system that regulates things like 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.

  • Get up slowly after sitting or lying down.

  • Drink more fluids to prevent dehydration.

  • Do not drink alcohol

  • 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 and medicine plan prescribed by your health care provider. Contact your provider with any questions or concerns.


Follow-up care

Follow up with your health care provider as advised.


When to get medical advice

Contact your health care provider or get medical care 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

  • Palpitations, or feeling as if your heart is skipping a beat

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

  • Fast racing heartbeat

  • Excessive sweating, or cold and clammy skin

© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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