From the Guidelines
A sodium level of 135 mEq/L is considered within the normal range, though at the lower end of normal (typically 135-145 mEq/L), and according to the most recent guidelines, no specific treatment is needed for this sodium level as it's not clinically significant 1.
Key Considerations
- The American Association for the Study of Liver Diseases recommends that mild hyponatremia (Na 126-135 mEq/L) in cirrhosis without symptoms does not require specific management apart from monitoring and water restriction 1.
- The management of hyponatremia should focus on correcting the underlying cause, and in cases of hypervolemic hyponatremia, discontinuation of intravenous fluid therapy and free water restriction should be considered 1.
- Regular monitoring is recommended if you have conditions like heart failure, kidney disease, or liver problems that can affect sodium balance 1.
Recommendations for Maintenance of Healthy Sodium Levels
- Ensure adequate hydration without overhydrating
- Consume a balanced diet with moderate salt intake
- Be aware that certain medications like diuretics, antidepressants, and some pain medications can affect sodium levels
- Sodium is essential for nerve and muscle function, fluid balance, and blood pressure regulation, and your body typically maintains sodium balance through kidney function and thirst mechanisms 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 can increase serum sodium levels to a normal range (>135 mEq/L) in patients with hyponatremia.
- The primary endpoint of the studies was to evaluate the effect of tolvaptan on serum sodium levels.
- Tolvaptan was shown to be effective in increasing serum sodium levels in patients with hyponatremia, including those with serum sodium levels <130 mEq/L and <125 mEq/L 2.
From the Research
Sodium Level of 135
- A sodium level of 135 mEq/L is considered to be at the lower limit of the normal range, as hyponatremia is defined as a serum sodium concentration of less than 135 mEq/L 3, 4, 5, 6.
- According to the studies, a sodium level of 135 mEq/L may not necessarily be associated with severe symptoms, but it can still cause mild symptoms such as nausea, vomiting, weakness, headache, and mild neurocognitive deficits 3, 4.
- The management of a patient with a sodium level of 135 mEq/L would depend on the underlying cause of the hyponatremia, as well as the patient's fluid volume status (hypovolemic, euvolemic, or hypervolemic) 3, 4, 5.
- Treatment options for hyponatremia include fluid restriction, isotonic saline infusions, urea, vaptans, and hypertonic saline, depending on the severity of the condition and the patient's symptoms 3, 4, 5, 7.
- It is essential to note that overly rapid correction of sodium concentration can cause osmotic demyelination syndrome, a rare but severe neurological condition 3, 4.