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

From the Guidelines

Hyponatremia should be treated with a focus on correcting the underlying cause, and for severe cases, hypertonic saline may be used with careful monitoring to avoid rapid correction, aiming for a serum sodium increase of up to 5 mmol/L in the first hour and a limit of 8-10 mmol/L every 24 hours thereafter, as recommended by the most recent guidelines 1.

Treatment Approach

The treatment of hyponatremia depends on its severity, onset speed, and underlying cause. For mild to moderate cases, fluid restriction to 800-1000 mL/day is often the first approach.

• Addressing the underlying cause is essential, which may include stopping medications that contribute to hyponatremia, treating conditions like SIADH, or managing heart failure or liver disease.
• For symptomatic or severe hyponatremia (sodium <120 mEq/L), hypertonic 3% saline may be administered intravenously at 1-2 mL/kg/hr, with careful monitoring to avoid correcting sodium levels too quickly.
• The correction rate should not exceed 8-10 mEq/L in 24 hours to prevent osmotic demyelination syndrome, as supported by recent guidelines 1.

Specific Considerations

• For SIADH-related hyponatremia, vasopressin receptor antagonists like tolvaptan (starting at 15 mg daily) may be used, but with caution and typically for short-term use 1.
• Salt tablets and loop diuretics like furosemide can help in specific situations.
• Potassium replacement should be considered if hypokalemia is present, as potassium correction contributes to sodium correction.

Monitoring and Prevention

• Regular monitoring of serum sodium levels is crucial during treatment to ensure appropriate correction rates and prevent complications.
• The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome, especially in patients with cirrhosis undergoing liver transplantation 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. Avoid fluid restriction during the first 24 hours of therapy.

• Treatment of hyponatremia: Tolvaptan can be used to treat clinically significant hypervolemic and euvolemic hyponatremia.
• Dosage: The usual starting dose is 15 mg once daily, which can be increased to 30 mg once daily, and then to a maximum of 60 mg once daily as needed.
• Important considerations: Avoid fluid restriction during the first 24 hours of therapy, and monitor serum sodium levels closely to avoid too rapid correction of hyponatremia 2, 2.

From the Research

Treatment Approaches for Hyponatremia

• The treatment of hyponatremia depends on the underlying cause, severity, and symptoms of the condition 3, 4, 5, 6.
• For patients with hypovolemic hyponatremia, treatment involves rehydration with isotonic saline 6.
• Hypervolemic hyponatremia is managed by addressing the underlying cause, such as heart failure, cirrhosis, or renal failure 3, 6.
• Euvolemic hyponatremia is managed by restricting free water intake, addressing the underlying cause, and occasionally with drugs such as vasopressin receptor antagonists (vaptans) 3, 6, 7.

Treatment of Symptomatic Hyponatremia

• Severely symptomatic hyponatremia is a medical emergency that requires urgent treatment with hypertonic saline to increase serum sodium levels 3, 4, 5.
• The goal of treatment is to increase serum sodium levels 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, 4.
• Overly rapid correction of chronic hyponatremia can cause osmotic demyelination, a rare but severe neurological condition 3, 5.

Use of Medications in Hyponatremia Treatment

• 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 (vaptans) are a new class of drugs that offer an additional treatment option for hyponatremic patients with euvolemic hyponatremia due to SIADH 7.
• Tolvaptan has been shown to be effective in raising serum sodium levels in a predictable fashion in patients with SIADH, with few side effects when serum sodium is frequently monitored and dosage is properly adjusted 7.