What is the recommended dosage of salt tabs (sodium chloride) for treating hyponatremia?

Dosage of Salt Tablets in Hyponatremia

Salt tablets (oral sodium chloride) are dosed at 100 mEq (approximately 6 grams) three times daily for mild to moderate hyponatremia when fluid restriction alone fails, particularly in SIADH. 1

When to Use Oral Sodium Chloride Tablets

Primary indication: Euvolemic hyponatremia (SIADH) that does not respond to fluid restriction of 1 L/day 1

• Nearly half of SIADH patients fail to respond to fluid restriction as first-line therapy 2
• Salt tablets serve as adjunctive therapy to fluid restriction, not as monotherapy 1
• Home preparation of sodium chloride supplements using table salt is NOT recommended due to potential formulation errors that could cause hypo- or hypernatremia 3

Specific Dosing Recommendations

Standard adult dose: 100 mEq (6 grams) orally three times daily 1

• This translates to approximately 18 grams of sodium chloride per day total 1
• For reference: 1 teaspoon of salt contains 2,300 mg (100 mEq) of sodium 3
• Monitor serum sodium levels every 4 hours initially, then daily once stable 1

Correction Rate Limits (Critical Safety Parameters)

Maximum correction rates to prevent osmotic demyelination syndrome:

• Standard patients: 8 mmol/L per 24 hours maximum 1, 4, 5
• High-risk patients (advanced liver disease, alcoholism, malnutrition, prior encephalopathy): 4-6 mmol/L per day 1, 6
• For severe symptoms: correct 6 mmol/L over first 6 hours or until symptoms resolve, but total correction must not exceed 8 mmol/L in 24 hours 1

Treatment Algorithm Based on Volume Status

Euvolemic Hyponatremia (SIADH)

1. First-line: Fluid restriction to 1 L/day 1, 2
2. Second-line (if no response): Add oral sodium chloride 100 mEq three times daily 1
3. Third-line: Consider urea or vaptans for resistant cases 1, 2

Hypovolemic Hyponatremia

• Do NOT use salt tablets 1
• Treat with isotonic saline (0.9% NaCl) for volume repletion 1, 5
• Urine sodium <30 mmol/L predicts good response to saline 1

Hypervolemic Hyponatremia (Heart Failure, Cirrhosis)

• Salt tablets are contraindicated 1
• Primary treatment: fluid restriction to 1-1.5 L/day for sodium <125 mmol/L 1
• Sodium restriction (not supplementation) is appropriate: 2-2.5 g/day (88-110 mmol/day) 1

Monitoring Requirements

During active treatment with salt tablets:

• Check serum sodium every 4 hours initially 1
• Once stable, transition to daily monitoring 1
• Calculate sodium deficit: Desired increase in Na (mEq/L) × (0.5 × ideal body weight in kg) 1

Special Populations Requiring Caution

Pediatric patients with CKD:

• Infants with polyuric salt-wasting CKD stages 3-5: 1-5 mmol Na/kg body weight/day 3
• Average dose used in studies: 3.2 ± 1.04 mmol/kg 3
• Adjust according to blood biochemistry results 3

Infants on peritoneal dialysis:

• Sodium supplements should be considered for all infants with CKD stage 5D on PD therapy due to substantial sodium losses 3

Common Pitfalls to Avoid

• Never use salt tablets in hypervolemic hyponatremia - this worsens fluid overload 1
• Never use salt tablets as monotherapy in SIADH - always combine with fluid restriction 1
• Never exceed 8 mmol/L correction in 24 hours - risks osmotic demyelination syndrome 1, 4, 6
• Never use home-prepared salt solutions - formulation errors can cause dangerous sodium swings 3
• Never use salt tablets in cerebral salt wasting - these patients need IV fluids and volume replacement, not oral supplementation 1

When Salt Tablets Are Insufficient

Escalate to hypertonic saline (3%) if:

• Severe symptoms develop (seizures, coma, altered mental status) 1, 5
• Sodium <120 mmol/L with neurological symptoms 1
• Patient cannot tolerate oral intake 5

Consider alternative therapies:

• Urea is highly effective for SIADH and may be preferred over vaptans 2
• Vaptans (tolvaptan 15 mg once daily) for resistant euvolemic/hypervolemic hyponatremia 1, 4