) is a prescription medication that belongs to a group of drugs known as vasopressin receptor antagonists. It is approved to increase blood sodium (salt) in people with low blood sodium levels due to certain medical conditions.
Sodium is an important element that the body needs to function normally. It helps maintain blood pressure
, and is necessary for the nerves and muscles to work properly. Sodium also helps control the balance of water in and around the cells of the body.
Hyponatremia is the medical term for low blood sodium. It generally occurs when there is too much water in the body. The excess water dilutes the sodium in the blood. The main types of hyponatremia are:
- Euvolemic hyponatremia -- which occurs when the amount of water in the body increases, and the amount of sodium does not change.
- Hypervolemic hyponatremia -- which occurs when both water and sodium levels increase, but water increases more.
- Hypovolemic hyponatremia -- which occurs when water and sodium are lost from the body, but more sodium is lost than water.
When hyponatremia occurs, the cells in the body begin to swell from too much water. This can lead to a variety of problems, especially when the cells in the brain swell.
The symptoms of hyponatremia can range from mild to life-threatening, depending on how quickly and how low sodium levels drop. Hyponatremia that develops within a couple of days is generally more dangerous than hyponatremia that happens slowly over a longer period of time. Some of the possible symptoms of hyponatremia include:
- Nausea and vomiting
- Weakness or lack of energy
- Irritability and restlessness
- Muscle weakness or spasms
There are several possible causes of hyponatremia. For some people, hyponatremia occurs due to medical conditions that cause an imbalance of water and sodium. For example, liver disease and heart failure
can cause the body to hold on to too much water, leading to hypervolemic hyponatremia.
Syndrome of inappropriate antidiuretic hormone (SIADH) is another medical condition that can cause hyponatremia. In SIADH, the body makes too much antidiuretic hormone. Antidiuretic hormone, also known as vasopressin, helps the body conserve water by reducing the amount of water that passes out of the body through the kidneys. When excess antidiuretic hormone is made, the body holds on to too much water.
Treatment for hyponatremia can vary. In most cases, your healthcare provider will want to treat the underlying cause. Depending on the severity of the hyponatremia, your healthcare provider may also recommend other treatments.
Samsca is used in people who have hypervolemic or euvolemic hyponatremia due to certain medical conditions, such as heart failure, liver disease, or SIADH. It should not be used in people who need their blood sodium levels raised immediately to prevent or treat serious nervous system symptoms.