How to correct hyponatremia

From the Guidelines

Correction of Hyponatremia

Correction of hyponatremia involves a tailored approach based on the underlying cause and severity of the condition. For mild to moderate hyponatremia, fluid restriction is often the initial treatment, with a goal of reducing daily fluid intake to 800-1000 mL, as suggested by 1, 2, 3.

Key Considerations

• In more severe cases, hypertonic saline (3% sodium chloride) may be administered at a dose of 1-2 mL/kg/hour for 3-4 hours, with close monitoring of serum sodium levels, as indicated by 1, 4.
• Medications such as tolvaptan (15-60 mg orally, once daily) or conivaptan (20-40 mg intravenously, every 1-2 days) may be used to increase serum sodium levels in patients with euvolemic or hypervolemic hyponatremia, as noted in 1, 5.
• The management of hypovolemic hyponatremia requires plasma volume expansion with saline solution and the correction of the causative factor, whereas hypervolemic hyponatremia involves attainment of a negative water balance, as discussed in 2, 3.

Treatment Approaches

• Fluid restriction should be reserved for those who are clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/L), as recommended by 4, 3.
• Hypertonic sodium chloride administration should be reserved for those who are severely symptomatic with acute hyponatraemia, with serum sodium corrected slowly, as advised by 4, 6.
• Vaptans, such as tolvaptan, have been shown to be effective in improving serum sodium concentration in patients with hypervolemic hyponatremia, as demonstrated in 1, 5.

Monitoring and Safety

• Close monitoring of serum sodium levels is crucial to avoid overcorrection and mitigate the risk of osmotic demyelination syndrome (ODS), as emphasized by 1, 5.
• Treatment should always be started in the hospital with close clinical monitoring and assessment of serum sodium levels, to avoid increases of serum sodium of more than 8-10 mmol/L/day, as recommended by 1.

From the FDA Drug Label

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. Avoid fluid restriction during the first 24 hours of therapy. 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

To correct hyponatremia, tolvaptan can be initiated at a dose of 15 mg once daily, with possible increases to 30 mg and 60 mg as needed, while monitoring serum sodium levels. It is essential to avoid fluid restriction during the first 24 hours of therapy and to monitor for changes in serum electrolytes and volume. Additionally, caution should be exercised to avoid too rapid correction of hyponatremia, which can cause serious neurologic sequelae, especially in susceptible patients 7.

From the Research

Correction of Hyponatremia

To correct hyponatremia, the following approaches can be taken:

• Treat the underlying cause of hyponatremia 8, 9, 10, 11, 12
• Categorize patients according to their fluid volume status (hypovolemic, euvolemic, or hypervolemic) 8, 10, 12
• Use the following treatments based on the type of hyponatremia: + Hypovolemic hyponatremia: rehydration with isotonic saline 10 + Euvolemic hyponatremia: restrict free water intake, address the underlying cause, and occasionally use drugs such as vasopressin receptor antagonists 10, 12 + Hypervolemic hyponatremia: address the underlying cause and use diuresis 10, 12
• For severely symptomatic hyponatremia, use hypertonic saline to increase the serum sodium level by 1-2 mmol/L per hour until symptoms abate 8, 9, 11, 12
• Monitor sodium levels frequently to avoid overly rapid correction, which can cause osmotic demyelination 8, 9, 11

Treatment Options

The following treatment options are available for hyponatremia:

• Urea: effective for treating the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure, but has adverse effects such as poor palatability and gastric intolerance 8
• Vaptans: effective for treating euvolemic and hypervolemic hyponatremia, but may cause overly rapid correction of hyponatremia and increased thirst 8, 12
• Hypertonic saline: reserved for patients with severely symptomatic hyponatremia, and should be administered with caution to avoid overly rapid correction 8, 9, 11, 12
• Fluid restriction: frequently employed to treat volume overload, and may be used in combination with other treatments 10, 12
• Loop diuretics: may be used to treat volume overload, especially in patients with heart failure or cirrhosis 9