Safety of Sodium Chloride 1 gm Tablets Three Times Daily for Hyponatremia
Sodium chloride 1 gm tablets three times daily (total 3 gm/day) is generally safe and appropriate for treating mild to moderate euvolemic hyponatremia (particularly SIADH) that has not responded to fluid restriction alone, but is NOT appropriate as monotherapy for severe symptomatic hyponatremia, which requires hypertonic saline. 1
When This Dose is Appropriate
For euvolemic hyponatremia (SIADH): If fluid restriction to 1 L/day fails to improve sodium levels, adding oral sodium chloride 100 mEq (approximately 6 gm) three times daily is recommended by neurosurgery guidelines 1. Your proposed dose of 1 gm three times daily (total 3 gm = approximately 50 mEq) represents a more conservative approach that may be reasonable for:
- Mild hyponatremia (130-134 mEq/L) with minimal symptoms 2
- Moderate hyponatremia (125-129 mEq/L) without severe neurological symptoms, as adjunctive therapy to fluid restriction 1, 2
- Patients who cannot tolerate higher sodium loads due to underlying conditions 2
Critical Safety Considerations
Maximum correction limits must be strictly observed: Never exceed 8 mmol/L correction in 24 hours to prevent osmotic demyelination syndrome 1, 3, 4. High-risk patients (advanced liver disease, alcoholism, malnutrition) require even slower correction at 4-6 mmol/L per day 1.
Monitor sodium levels frequently: Check serum sodium every 4 hours initially when starting oral sodium supplementation, then daily once stable 1. This frequent monitoring is essential because the response to oral sodium is less predictable than intravenous hypertonic saline 5.
When This Dose is NOT Appropriate
Severe symptomatic hyponatremia (seizures, coma, altered mental status) requires immediate 3% hypertonic saline with target correction of 6 mmol/L over 6 hours, not oral tablets 1, 4, 2. This is a medical emergency that cannot be adequately treated with oral sodium 1.
Hypervolemic hyponatremia (heart failure, cirrhosis): Oral sodium supplementation will worsen fluid overload and edema 1. These patients require fluid restriction to 1-1.5 L/day, not sodium supplementation 1, 2.
Hypovolemic hyponatremia: These patients need volume repletion with isotonic saline (0.9% NaCl), not oral sodium tablets 1, 2.
Practical Implementation
Calculate expected sodium increase: Using the formula from neurosurgery guidelines, sodium deficit = desired increase (mEq/L) × (0.5 × ideal body weight in kg) 1. Your 3 gm daily dose provides approximately 50 mEq sodium, which in a 70 kg patient would theoretically increase sodium by roughly 1.4 mEq/L per day—well within safe limits 1.
Combine with fluid restriction: Oral sodium supplementation works best when combined with fluid restriction to 1 L/day for SIADH 1, 3. Salt tablets alone without fluid restriction are often ineffective 3.
Consider higher doses if needed: If 3 gm/day proves insufficient, guidelines support increasing to 100 mEq (approximately 6 gm) three times daily for SIADH refractory to fluid restriction 1. However, this higher dose requires even more careful monitoring 1.
Alternative Considerations
Urea may be more effective: Recent evidence suggests oral urea is considered very effective and safe for SIADH, potentially more so than sodium tablets 3. Urea and vaptans are now considered the most effective second-line therapies when fluid restriction fails 3, 4.
Home preparation is not recommended: Using table salt to prepare sodium supplements carries risk of formulation errors and is not advised 1.