What is the recommended dose of sodium chloride (salt) tablets for treating hyponatremia?

Oral Sodium Chloride Tablets for Hyponatremia: Dosing Recommendations

For mild to moderate hyponatremia requiring oral sodium supplementation, prescribe sodium chloride 100 mEq (approximately 6 grams) orally three times daily, combined with fluid restriction to 1 liter per day. 1

Dosing Based on Clinical Scenario

For SIADH (Euvolemic Hyponatremia)

• First-line: Fluid restriction to 1 L/day 2, 1
• If no response to fluid restriction: Add oral sodium chloride 100 mEq three times daily 2, 1
• Augment with high protein diet to increase solute intake 1

For Mild Symptomatic or Asymptomatic Hyponatremia (Na 120-135 mmol/L)

• Sodium chloride 100 mEq orally three times daily 1
• Combine with fluid restriction 1-1.5 L/day 2, 1
• This approach is appropriate for patients without severe neurological symptoms 1

For Hypervolemic Hyponatremia (Cirrhosis, Heart Failure)

• Primary treatment: Fluid restriction to 1-1.5 L/day for Na <125 mmol/L 2, 1
• Discontinue diuretics temporarily if contributing 2
• Oral salt tablets are not first-line in this population—sodium restriction (not supplementation) is often needed 3, 2

Critical Safety Parameters

Correction Rate Limits

• Maximum correction: 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 2, 1
• Target correction: 4-6 mmol/L per day for most patients 2, 1
• High-risk patients (cirrhosis, alcoholism, malnutrition, advanced liver disease): Limit to 4-6 mmol/L per day 2, 1

Monitoring Requirements

• Check serum sodium every 4-6 hours during initial correction 1
• Calculate sodium deficit: Desired increase in Na (mEq/L) × (0.5 × ideal body weight in kg) 2, 1
• Monitor for hyperkalemia, especially with renal impairment 1

When NOT to Use Oral Salt Tablets

Absolute Contraindications

• Severe symptomatic hyponatremia (seizures, coma, altered mental status): Requires 3% hypertonic saline immediately, not oral tablets 2, 1, 4
• Hypervolemic states (volume overload, ascites, edema): Salt tablets worsen fluid retention 3, 2
• Severe renal failure (GFR <10): Cannot handle sodium load appropriately 2

Relative Contraindications

• Heart failure with volume overload 2
• Cirrhosis with ascites—fluid restriction is preferred over sodium supplementation 3, 2

Practical Formulation Details

FDA-approved oral sodium chloride solution (23.4%): 5

• Dosing: 4 mL provides 936 mg sodium chloride (equivalent to 368 mg elemental sodium) 5
• To achieve 100 mEq sodium: Approximately 6 grams sodium chloride (100 mEq = ~5.8 grams NaCl) 1
• Home preparation with table salt is NOT recommended due to formulation errors 1

Common Pitfalls to Avoid

• Never ignore mild hyponatremia (130-135 mmol/L): Even mild hyponatremia increases fall risk (21% vs 5%) and mortality (60-fold increase at Na <130 mmol/L) 2, 4
• Never exceed 8 mmol/L correction in 24 hours: Overcorrection risks osmotic demyelination syndrome, which can cause quadriparesis, dysarthria, or death 2, 1
• Never use oral salt tablets as monotherapy for severe symptomatic hyponatremia: This is a medical emergency requiring IV hypertonic saline 2, 1, 4
• Never use salt tablets in hypervolemic hyponatremia without addressing volume status first: This worsens edema and ascites 3, 2

Special Population Considerations

Neurosurgical Patients

• Distinguish cerebral salt wasting (CSW) from SIADH 2, 1
• CSW requires volume and sodium replacement, not fluid restriction 2, 1
• Consider fludrocortisone 0.1-0.2 mg daily for severe CSW 2, 1

Cirrhotic Patients

• Hyponatremia increases risk of spontaneous bacterial peritonitis (OR 3.40), hepatorenal syndrome (OR 3.45), and hepatic encephalopathy (OR 2.36) 2
• Fluid restriction to 1-1.5 L/day is preferred over salt supplementation 3, 2
• Consider albumin infusion alongside fluid restriction 2, 1