Hyponatremia
Medically reviewed by Drugs.com. Last updated on Apr 6, 2025.
What is hyponatremia?
Hyponatremia occurs when the amount of sodium (salt) in your blood is lower than normal. Sodium is an electrolyte (mineral) that helps your muscles, heart, and digestive system work properly. It helps control blood pressure and fluid balance.
What causes or increases my risk for hyponatremia?
- A diet that is low in sodium
- Drinking too much water or receiving too much fluid through an IV
- Intense exercise that lasts a long time and causes heavy sweating
- A medical condition, such as Addison disease, kidney disease, or congestive heart failure
- Medicines such as diuretics, antidepressants, pain medicines, or ecstasy
- Dehydration
What are the signs and symptoms of hyponatremia?
You may have no signs or symptoms. Symptoms may start to appear when the amount of sodium in your blood drops too low or too fast. You may have any of the following:
- Swelling in areas such as your ankles from fluid retention
- Abdominal cramps, nausea, or vomiting
- Headache, confusion, hallucinations, or trouble staying awake
- Muscle weakness or cramps
- Seizures or coma
How is hyponatremia diagnosed?
Your healthcare provider will ask you about the medicines you take. Your provider will do a physical exam to look for signs of swelling caused by fluid retention.
- Blood tests will be done to check the level of sodium in your blood. They may also be done to find the cause of your hyponatremia.
- Urine sodium is a test that checks the level of sodium in your urine. A sample of your urine is collected and is sent to a lab for tests.
Drugs used to treat this and similar conditions
How is hyponatremia treated?
Treatment depends on the cause of your hyponatremia and how severe it is. Healthcare providers may limit the amount of liquids you drink if you are retaining water. A salt solution may be given through an IV to increase the amount of sodium in your blood. Medicines may also be given to help get rid of extra fluid in your body. You may urinate more often while taking these medicines.
Treatment options
The following list of medications are related to or used in the treatment of this condition.
Call your local emergency number (911 in the US) or have someone call if:
- You have a seizure.
- You have trouble breathing.
- You are confused or cannot think clearly.
When should I seek immediate care?
- You have an irregular heartbeat.
When should I call my doctor?
- You have muscle cramps or twitching.
- You feel very weak or tired.
- You have nausea or are vomiting.
- You have questions or concerns about your condition or care.
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