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

From the Guidelines

Hyponatremia treatment should be tailored to its severity, cause, and symptoms, with the goal of correcting serum sodium levels while minimizing the risk of osmotic demyelination syndrome, as recommended by the most recent guidelines 1.

Key Considerations

• The treatment approach depends on the type of hyponatremia: hypovolemic, euvolemic, or hypervolemic.
• For hypovolemic hyponatremia, treatment involves fluid resuscitation with 5% IV albumin or crystalloid solution, and addressing the underlying cause.
• For euvolemic hyponatremia, management is based on the specific underlying cause.
• For hypervolemic hyponatremia, treatment includes fluid restriction, reduction or discontinuation of diuretics and laxatives, administration of hyperoncotic albumin, and/or vasopressin receptor antagonists (“vaptans”).

Correction Rates

• The correction rate should not exceed 8-10 mEq/L in 24 hours to prevent osmotic demyelination syndrome, as recommended by recent studies 1.
• For severely symptomatic hyponatremia, 3% hypertonic saline may be administered at 100-150 mL over 10-20 minutes, with careful monitoring of serum sodium levels.

Monitoring and Education

• Regular monitoring of serum sodium levels (every 2-4 hours initially for severe cases) is essential to ensure appropriate correction rates.
• Patients should be educated about fluid restrictions and symptoms requiring medical attention.

Vasopressin Receptor Antagonists

• For SIADH, vasopressin receptor antagonists such as tolvaptan (starting at 15 mg daily) may be used, with careful monitoring of serum sodium levels and potential side effects 1.

From the FDA Drug Label

The dose of tolvaptan could be increased at 24-hour intervals to 30 mg once daily, then to 60 mg once daily, until either the maximum dose of 60 mg or normonatremia (serum sodium >135 mEq/L) was reached Fluid restriction was to be avoided if possible during the first 24 hours of therapy to avoid overly rapid correction of serum sodium, and during the first 24 hours of therapy 87% of patients had no fluid restriction. Thereafter, patients could resume or initiate fluid restriction (defined as daily fluid intake of ≤1. 0 liter/day) as clinically indicated.

To treat hyponatremia, tolvaptan can be initiated at an oral dose of 15 mg once daily, with possible increases to 30 mg once daily, then to 60 mg once daily, until either the maximum dose of 60 mg or normonatremia (serum sodium >135 mEq/L) is reached.

• Fluid restriction should be avoided during the first 24 hours of therapy to prevent overly rapid correction of serum sodium.
• After the first 24 hours, patients can resume or initiate fluid restriction (defined as daily fluid intake of ≤1.0 liter/day) as clinically indicated 2.

From the Research

Treatment Approaches for Hyponatremia

• The approach to managing hyponatremia should consist of treating the underlying cause 3.
• Patients should be categorized according to their fluid volume status (hypovolemic hyponatremia, euvolemic hyponatremia, or hypervolemic hyponatremia) 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.
• Vasopressin receptor antagonists (VRA) can induce urinary dilution with an aquaresis that leads to an increase in serum sodium concentration 4.
• VRA have been approved for use in patients with euvolemic and hypervolemic hyponatremia 4.

Management of Severely Symptomatic Hyponatremia

• Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency 3.
• US and European guidelines recommend treating severely symptomatic hyponatremia with bolus hypertonic saline to reverse hyponatremic encephalopathy by increasing the serum sodium level by 4 mEq/L to 6 mEq/L within 1 to 2 hours but by no more than 10 mEq/L (correction limit) within the first 24 hours 3.
• Overly rapid correction of chronic hyponatremia may cause osmotic demyelination, a rare but severe neurological condition, which can result in parkinsonism, quadriparesis, or even death 3, 5.

Treatment Options for Hyponatremia in Heart Failure

• Hyponatremia is a common electrolyte disorder in patients with heart failure, and is associated with increased morbidity and mortality 6.
• Treatment options for hyponatremia in heart failure, such as water restriction or the use of hypertonic saline with loop diuretics, have limited efficacy 6.
• Arginine vasopressin (AVP)-receptor antagonists increase sodium levels effectively and their use seems promising in patients with hyponatremia 6.