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Side Effect: Low Blood Sodium (hyponatremia)

What is Low Blood Sodium (hyponatremia)?

Low blood sodium level, also known as hyponatremia, is a medical condition characterized by a lower than normal concentration of sodium (Na+) ions in the blood.

What does Low Blood Sodium (hyponatremia) look like?

Hyponatremia can cause a wide range of symptoms, including nausea, vomiting, dizziness, weakness, muscle cramps, headache, confusion, seizures, and even coma. In severe cases, it can be life-threatening. Symptoms may depend upon how quickly the Na+ levels in the blood drop, and how low they get.

Low Blood Sodium (hyponatremia)

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Who gets Low Blood Sodium (hyponatremia)?

There are several risk factors for hyponatremia in cancer patients. In many cases, several risk factors are present in patients who experience hyponatremia. Risk factors include:

How to prevent Low Blood Sodium (hyponatremia)

The prevention of hyponatremia in cancer patients involves careful monitoring of fluid intake and output, IV fluid type, treating underlying medical conditions, and adjusting any possible contributing medications.

How to treat Low Blood Sodium (hyponatremia)

The treatment of hyponatremia in patients with cancer starts with addressing the underlying cause. Additional treatment approaches include fluid restriction, concentrated intravenous saline solutions, salt tablets taken by mouth, careful use of diuretics, or medications such as tolvaptan (Samsca®) and conivaptan (Vaprisol®).

If Na+ are very low, raising the sodium levels in the blood must be done slowly over time as rapid increases can cause seizures, or life-threatening neurological damage.


1) Berardi R, Torniai M, Lenci E, et al. Electrolyte disorders in cancer patients: a systematic review. J Cancer Metastasis Treat 2019;5:79.

2) Castillo JJ, Vincent M, and Justice E, et al. Diagnosis and Management of Hyponatremia in Cancer Patients. Oncologist 2012; 17(6):756–765.

Created: February 9, 2024 Updated: March 6, 2024