What is the treatment for hyponatremia (low sodium level) with a sodium level of 135 milliequivalents per liter (mEq/L)?

From the Guidelines

For a patient with a sodium level of 135 mEq/L, which is at the lower end of the normal range, no specific treatment is required unless the patient is symptomatic, according to the most recent guidance from the American Association for the Study of Liver Diseases 1.

Key Considerations

• The focus should be on identifying and addressing the underlying cause, which could include medication effects, syndrome of inappropriate antidiuretic hormone secretion (SIADH), heart failure, liver disease, or kidney problems.
• If treatment is needed, fluid restriction to 1-1.5 liters per day is often the first step for mild cases.
• For symptomatic patients or those with more severe hyponatremia, options include isotonic saline (0.9% sodium chloride) infusion, hypertonic saline (3% sodium chloride) for severe cases, or oral sodium chloride tablets.
• Medications like tolvaptan or conivaptan (vasopressin receptor antagonists) might be considered in specific situations, as they can raise serum sodium during treatment, but should be used with caution and only for a short term (≤30 days) 1.

Correction Rate

• The correction rate should not exceed 8 mEq/L in 24 hours to prevent osmotic demyelination syndrome, as recommended by the guidelines 1.

Underlying Condition

• Treating the underlying condition is crucial for long-term management, as is regular monitoring of sodium levels during correction.

Specific Guidance

• For patients with cirrhosis, mild hyponatremia (Na 126-135 mEq/L) without symptoms does not require specific management apart from monitoring and water restriction, as per the 2021 practice guidance by the American Association for the Study of Liver Diseases 1.
• Hypertonic saline is reserved for short-term treatment of patients with symptomatic or severe hyponatremia or those with imminent liver transplant, and its use should be guided by the risk of worsening fluid overload and the need to prevent rapid increase in serum sodium 1.

From the FDA Drug Label

In two double-blind, placebo-controlled, multi-center studies (SALT-1 and SALT-2), a total of 424 patients with euvolemic or hypervolemic hyponatremia (serum sodium <135 mEq/L) resulting from a variety of underlying causes (heart failure, liver cirrhosis, syndrome of inappropriate antidiuretic hormone [SIADH] and others) were treated for 30 days with tolvaptan or placebo, then followed for an additional 7 days after withdrawal. The primary endpoint for these studies was the average daily AUC for change in serum sodium from baseline to Day 4 and baseline to Day 30 in patients with a serum sodium less than 135 mEq/L. Compared to placebo, tolvaptan caused a statistically greater increase in serum sodium ( p <0. 0001) during both periods in both studies

Tolvaptan treatment can increase serum sodium levels in patients with hyponatremia.

• The studies showed a statistically significant increase in serum sodium levels in patients treated with tolvaptan compared to placebo.
• The effect of tolvaptan on serum sodium levels was seen across all disease etiology subsets, including heart failure, liver cirrhosis, and SIADH.
• The primary endpoint of the studies was the average daily AUC for change in serum sodium from baseline to Day 4 and baseline to Day 30 in patients with a serum sodium less than 135 mEq/L 2.

From the Research

Sodium 135 Treatment

• Sodium 135 treatment refers to the management of hyponatremia, a condition where the serum sodium level is less than 135 mEq/L 3.
• Hyponatremia is the most common electrolyte disorder and affects approximately 5% of adults and 35% of hospitalized patients 3.
• The treatment approach for hyponatremia depends on the underlying cause, fluid volume status, and symptom severity 3, 4.

Treatment Options

• For patients with severely symptomatic hyponatremia, bolus hypertonic saline is recommended to increase the serum sodium level by 4-6 mEq/L within 1-2 hours 3.
• Urea and vaptans can be effective treatments for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure 3, 5.
• Fluid restriction, isotonic saline, and loop diuretics are also used to treat hyponatremia, depending on the patient's fluid volume status and underlying cause 4, 6.
• Vasopressin receptor antagonists (VRAs) have shown promise in the treatment of euvolemic and hypervolemic hyponatremia, with significant increases in serum sodium concentration and urine output 7.

Considerations

• Overly rapid correction of chronic hyponatremia can cause osmotic demyelination, a rare but severe neurological condition 3.
• The choice of treatment should be individualized based on the patient's specific condition, and careful monitoring of serum sodium levels and clinical symptoms is essential 3, 6.
• Further research is needed to compare the efficacy and side effects of different treatment options, including urea therapy and vaptans 6.