Oral Sodium Chloride use in hyponatraemia

AVAILABILITY: 
Sodium Chloride Powder [1 g = 17mmol]
NaCl 3% [1 L = 513 meq]
NaCl 0.9% [1 L = 154 meq]

• In theory, oral sodium chloride might be an option for patients with chronic hyponatremia. However, randomized trials comparing oral with intravenous sodium chloride for the management of hyponatremia have not been performed. 
• Traditionally 1-2 g three times daily has been used when sodium chloride was given orally, but no consistent dosing strategy for oral sodium chloride in patients with hyponatremia is available in the published literature. 
• Gastrointestinal intolerance (e.g., nausea, vomiting, diarrhea) is a potential problem with oral therapy. The response (serum changes) is also unpredictable. 
• Patients with syndrome of inappropriate antidiuretic hormone secretion (SIADH) who have very mild or absent symptoms and a serum sodium above 120 meq/L can be treated with oral salt tablets in addition to fluid restriction. 
• Given hourly, salt tablets can substitute for hypertonic saline in nonurgent situations. 
• Oral salt tablets may also be effective in hypovolemic patients who are treated as outpatients (in combination with reversing the cause of hypovolemia)
• Calculating the dose of oral salt tablets uses the same principles as intravenous isotonic or hypertonic saline: 9 g of oral salt provides a similar quantity of sodium as 1 L of isotonic saline (154 meq) but without any water; 1 g of oral salt is equivalent to 35 mL of 3 percent saline.
• Oral salt tablets should not be given to edematous patients (eg, those with heart failure, cirrhosis)

reference:

1. www.uptodate.com

2. http://www.ashpmedia.org/advantage/hyponatremia/docs/hyponatremia_e-newsletter_3-2012.pdf

3. http://www.ncbi.nlm.nih.gov/pubmed/23816479