What is the dosing for oral sodium (Na+) supplements in patients with hyponatremia?

Oral Sodium Supplementation Dosing in Hyponatremia

For patients with hyponatremia requiring oral sodium supplementation, the recommended dose is 100 mEq of oral sodium chloride three times daily, which should be adjusted based on serum sodium response and symptom severity. 1

Dosing Based on Symptom Severity and Volume Status

Severe Symptomatic Hyponatremia

• For patients with severe symptoms (mental status changes, seizures, coma):
  • Initial treatment should be with 3% hypertonic saline, not oral supplements 1, 2
  • Target correction of 6 mmol/L over 6 hours or until severe symptoms resolve 1
  • Total correction should not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 2

Mild to Moderate Symptomatic Hyponatremia

• For patients with mild symptoms (nausea, vomiting, headache) or serum sodium <120-125 mmol/L:
  • NaCl 100 mEq orally three times daily 1
  • Combined with fluid restriction to 1 L/day 1
  • High protein diet to augment solute intake 1

Asymptomatic Hyponatremia

• For patients with no symptoms:
  • Fluid restriction (1-1.5 L/day) is the primary approach 1, 3
  • If no response to fluid restriction, add oral sodium supplementation 1, 4
  • Adequate solute intake with dietary salt and protein is recommended 3

Specific Considerations by Etiology

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

• First-line: Fluid restriction to 1 L/day 1, 2
• If no response to fluid restriction:
  • Add NaCl 100 mEq orally three times daily 1
  • Consider urea (30-40 g/day) as an alternative second-line therapy 4
  • Tolvaptan may be considered for refractory cases, starting at 15 mg once daily, titrating up to 60 mg if needed 5

Cerebral Salt Wasting (CSW)

• Volume repletion with normal saline is the primary approach 1
• Oral sodium supplementation can be added if needed 1
• Fludrocortisone (0.1 mg three times daily) may be beneficial 1

Cirrhosis with Hyponatremia

• Fluid restriction to 1-1.5 L/day for severe hyponatremia (Na <120 mmol/L) 1
• Discontinue diuretics if they're contributing to hyponatremia 1
• Avoid rapid correction with hypertonic saline as it can lead to complications 1

Monitoring and Safety Considerations

• Monitor serum sodium every 4-6 hours during initial correction 1, 2
• Calculate sodium deficit using formula: Desired increase in Na (mEq/L) × (0.5 × ideal body weight in kg) 1
• Never exceed correction of 8 mmol/L in 24 hours for chronic hyponatremia 1, 2
• Be vigilant for signs of overcorrection, which can lead to osmotic demyelination syndrome 2, 6
• Monitor for hyperkalemia when using oral sodium supplements, especially in patients with renal impairment 1

Practical Considerations

• Oral sodium tablets are often poorly tolerated due to gastric irritation and taste 4
• Sodium chloride tablets typically come in 1 g (17 mEq) formulations, requiring multiple tablets per dose 6, 7
• For patients unable to tolerate tablets, sodium can be administered in broth or as salt added to food 7
• Duration of therapy depends on clinical response and underlying cause 1, 3

Cautions

• Avoid oral sodium supplementation in hypervolemic hyponatremia (heart failure, cirrhosis) unless directed by specialist 1, 6
• Rapid correction can lead to osmotic demyelination syndrome, particularly in alcoholics, malnourished patients, and those with liver disease 5, 6
• Tolvaptan should be initiated in a hospital setting with close monitoring of serum sodium 5