Hyponatremia Drug Summary

Last updated: 18 July 2025
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Diuretics

Drug Dosage Remarks
Vasopressin Receptor Antagonists
Conivaptan Loading dose: 20 mg IV infusion over 30 minutes
Followed by 20 mg continuous IV infusion over 24 hours x 2-4 days
Max dose: 40 mg IV infusion over 24 hours x 4 days
Max duration of therapy: ≤4 days		 Adverse Reactions
  • CV effects (orthostatic hypotension, hypertension); Metabolic effects (hypokalemia, hyponatremia); GI effects (constipation, vomiting, diarrhea); Local reactions (erythema at injection site, pain, phlebitis, swelling); Other effects (fever, headache, thirst)
Special Instructions
  • Avoid in patients with hypovolemic hyponatremia and anuria
  • Avoid co-administration with strong CYP3A4 inhibitors (eg Ketoconazole, Itraconazole, Clarithromycin, Indinavir)
  • Discontinue treatment if the patient developed excessive rise in serum sodium concentration, hypovolemia or hypotension
  • Monitor frequently serum sodium concentrations and volume status during therapy
Tolvaptan Initial dose: 15 mg PO 24 hourly
May be increased to 30 mg PO 24 hourly after at least 24 hours
Max dose: 60 mg PO 24 hourly
Max duration of therapy: ≤30 days
Serum Na <125 mEq/L in patients whom rapid volume decrease is inappropriate: 7.5 mg PO 24 hourly as initial dose		 Adverse Reactions
  • GI effect (constipation); Other effects (thirst, dry mouth, pollakiuria or polyuria, asthenia, hyperglycemia, fever, orthostatic hypotension, anorexia)
Special Instructions
  • Avoid in patients with hypovolemic hyponatremia and anuria
  • Avoid grapefruit juice and co-administration with strong CYP3A inhibitors (eg Ketoconazole, Itraconazole, Clarithromycin, Indinavir)
  • Do not administer for >30 days to have a lesser risk of liver injury
  • Monitor frequently serum sodium concentrations and volume status during therapy

Electrolytes

Drug Dosage Remarks
Sodium chloride (3%) 100-150 mL IV bolus over 10-20 minutes
May repeat dose up to 3 times		 Adverse Reactions
  • CV effect (venous thrombosis or phlebitis); Metabolic effects (hypervolemia, hypernatremia); Other effects (fever, injection site infection)
Special Instructions
  • Evaluate changes in fluid balance, electrolyte concentration and acid-base balance
  • Use with caution in patients with chronic heart failure or edematous or sodium-retaining conditions, severe renal insufficiency, liver cirrhosis and receiving corticosteroids or Corticotropin

Disclaimer

All dosage recommendations are for non-pregnant and non-breastfeeding women, and non-elderly adults with normal renal and hepatic function unless otherwise stated.  
Not all products are available or approved for above use in all countries.
Products listed in the Drug Summary are based on indications stated in the locally approved product monographs.   
Please refer to local product monographs in Related MIMS Drugs for country-specific prescribing information.  

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