What is the treatment for hyponatremia (low sodium levels)?

From the Guidelines

Hyponatremia treatment should prioritize the correction of serum sodium levels while minimizing the risk of osmotic demyelination syndrome, with the most recent and highest quality study recommending a correction rate of up to 5 mmol/L in the first hour and a limit of 8–10 mmol/L every 24 hours thereafter until the serum sodium concentration reaches 130 mmol/L 1.

Treatment Approach

The treatment of hyponatremia depends on the severity, symptoms, and underlying cause. For mild to moderate asymptomatic hyponatremia (sodium >125 mEq/L), fluid restriction to 800-1000 mL/day is often sufficient, along with addressing the underlying cause such as discontinuing offending medications or treating SIADH.

• For symptomatic or severe hyponatremia (<125 mEq/L), 3% hypertonic saline is administered, typically starting at 100-150 mL over 10-20 minutes, which can be repeated if symptoms persist.
• The correction rate should not exceed 8-10 mEq/L in 24 hours to prevent osmotic demyelination syndrome, as recommended by recent guidelines 1.
• For SIADH-related hyponatremia, vasopressin receptor antagonists like tolvaptan (starting at 15 mg daily) may be used, but with caution due to potential liver toxicity 1.
• Loop diuretics such as furosemide (20-40 mg IV) can help with volume overload states.

Monitoring and Adjunctive Therapy

• Sodium correction must be carefully monitored with serial sodium measurements every 2-4 hours during active treatment.
• Potassium replacement should be considered simultaneously as it contributes to sodium correction.
• The treatment approach balances the risks of hyponatremia complications against those of overly rapid correction, with the goal of safely normalizing serum sodium while addressing the underlying etiology, as emphasized in recent studies 1.

From the FDA Drug Label

Tolvaptan tablets are indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia (serum sodium <125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction), including patients with heart failure and Syndrome of Inappropriate Antidiuretic Hormone (SIADH) The usual starting dose for tolvaptan tablets is 15 mg administered once daily without regard to meals. Increase the dose to 30 mg once daily, after at least 24 hours, to a maximum of 60 mg once daily, as needed to achieve the desired level of serum sodium. Too rapid correction of hyponatremia (e.g., > 12 mEq/L/24 hours) can cause osmotic demyelination resulting in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma and death. In susceptible patients, including those with severe malnutrition, alcoholism or advanced liver disease, slower rates of correction may be advisable

Hyponatremia Treatment with Tolvaptan:

• Tolvaptan is indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia.
• The starting dose is 15 mg once daily, which can be increased to 30 mg and then 60 mg once daily as needed.
• Key Considerations:
  • Avoid too rapid correction of hyponatremia (> 12 mEq/L/24 hours) to prevent osmotic demyelination.
  • Monitor serum sodium levels closely, especially in susceptible patients (e.g., those with severe malnutrition, alcoholism, or advanced liver disease).
  • Tolvaptan should be initiated and re-initiated in a hospital setting where serum sodium can be closely monitored 2, 2.

From the Research

Hyponatremia Treatment Overview

• Hyponatremia is a common electrolyte disorder that affects approximately 5% of adults and 35% of hospitalized patients 3.
• The treatment of hyponatremia depends on the presence and severity of symptoms, as well as the underlying cause of the condition 3, 4, 5.

Treatment Approaches

• For most patients, the approach to managing hyponatremia should consist of treating the underlying cause 3.
• Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but have adverse effects 3.
• Hypertonic saline is reserved for patients with severely symptomatic hyponatremia, and is recommended to be administered as a bolus injection to reverse hyponatremic encephalopathy 3, 6, 4, 5.

Severe Hyponatremia Treatment

• Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency that requires immediate treatment with hypertonic saline 3, 4, 5.
• The goal of treatment is to increase the serum sodium level by 4-6 mEq/L within 1-2 hours, but not to exceed a correction limit of 10 mEq/L within the first 24 hours 3.

Chronic Hyponatremia Treatment

• Mild chronic hyponatremia is associated with cognitive impairment, gait disturbances, and increased rates of falls and fractures 3.
• The treatment of chronic hyponatremia depends on the underlying cause and the presence of symptoms, and may involve fluid restriction, urea, vaptans, or loop diuretics 3, 5, 7.

Guidelines and Recommendations

• The European Society of Intensive Care Medicine, the European Society of Endocrinology, and the European Renal Association-European Dialysis and Transplant Association have developed clinical practice guidelines on the diagnostic approach and treatment of hyponatremia 7.
• The guidelines recommend a physiological approach to determine the cause of hyponatremia and to guide treatment, and emphasize the importance of avoiding overly rapid correction of hyponatremia to prevent osmotic demyelination 4, 5.