Salt Tablets in Hyponatremia Treatment
Salt tablets are effective for treating euvolemic hyponatremia, increasing serum sodium by approximately 5.2 mEq/L over 48 hours, but should NOT be used in hypervolemic hyponatremia (heart failure, cirrhosis) where they worsen fluid overload. 1
When Salt Tablets Are Appropriate
Euvolemic Hyponatremia (SIADH)
- Salt tablets (sodium chloride 100 mEq three times daily) should be added when fluid restriction alone fails to correct hyponatremia 2
- The typical dose is 4 mL of 23.4% sodium chloride oral solution (equivalent to 936 mg) for adults ages 9-50, providing 368 mg of elemental sodium per dose 3
- Salt tablets work by providing additional sodium intake while maintaining fluid restriction to 1 L/day 2, 4
- Research demonstrates salt tablets increase serum sodium by 5.2 mEq/L over 48 hours compared to 3.1 mEq/L without salt tablets (P < 0.001) 1
Mild Hyponatremia (126-135 mmol/L)
- For asymptomatic patients with sodium 126-135 mmol/L and normal creatinine, continue monitoring without water restriction 5, 2
- Salt tablets combined with adequate protein intake can be used as first-line therapy alongside fluid restriction 6
When Salt Tablets Are CONTRAINDICATED
Hypervolemic Hyponatremia
- Never use salt tablets in heart failure or cirrhosis patients with hyponatremia—they worsen edema and ascites 2
- These patients require fluid restriction to 1-1.5 L/day for sodium <125 mmol/L, NOT sodium supplementation 5, 2
- In cirrhosis, sodium restriction (not supplementation) results in weight loss as fluid follows sodium 5, 2
Severe Symptomatic Hyponatremia
- Salt tablets are too slow for severe symptoms (seizures, altered mental status, coma) 2, 7
- These patients require 3% hypertonic saline with target correction of 6 mmol/L over 6 hours 2, 7
Hypovolemic Hyponatremia
- Salt tablets are inappropriate—these patients need isotonic saline (0.9% NaCl) for volume repletion 2, 8
- Urine sodium <30 mmol/L predicts good response to saline infusion 2
Critical Safety Considerations
Correction Rate Limits
- Maximum correction must not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 2, 7, 4
- High-risk patients (cirrhosis, alcoholism, malnutrition) require slower correction at 4-6 mmol/L per day 2, 7
- Monitor serum sodium every 24 hours initially when using salt tablets 2
Treatment Algorithm for Euvolemic Hyponatremia
- First-line: Fluid restriction to 1 L/day 2, 4
- Second-line (if no response after 48 hours): Add salt tablets 100 mEq three times daily 2
- Third-line (if still refractory): Consider urea or vaptans (tolvaptan 15 mg daily) 2, 6, 4
Common Pitfalls to Avoid
- Using salt tablets in hypervolemic states worsens volume overload 2
- Ignoring mild hyponatremia (130-135 mmol/L) increases fall risk (21% vs 5%) and mortality 2, 7
- Failing to distinguish SIADH from cerebral salt wasting in neurosurgical patients—CSW requires volume replacement, not salt tablets 2
- Exceeding 8 mmol/L correction in 24 hours risks osmotic demyelination syndrome 2, 7, 4