What medications are used to decrease sodium levels in patients with hypernatremia?

Medications for Decreasing Sodium Levels in Hypernatremia

Loop diuretics are the primary medications used to decrease sodium levels in patients with hypernatremia, with furosemide being the most commonly prescribed agent due to its effectiveness in promoting sodium excretion.

Diuretic Options for Managing Hypernatremia

Loop Diuretics (First-Line)

• Furosemide (20-40 mg initially, maximum 600 mg daily) is the most commonly used loop diuretic for sodium reduction, acting at the loop of Henle to increase sodium excretion up to 20-25% of filtered load 1
• Bumetanide (0.5-1.0 mg initially, maximum 10 mg daily) may be preferred in some patients due to superior absorption and bioavailability compared to furosemide 1, 2
• Torsemide (10-20 mg initially, maximum 200 mg daily) offers longer duration of action (12-16 hours) compared to furosemide (6-8 hours) 1

Thiazide Diuretics (Second-Line or Combination Therapy)

• Chlorthalidone (12.5-25 mg daily, maximum 100 mg) has a longer duration of action (24-72 hours) than other thiazides 1, 2
• Hydrochlorothiazide (25 mg once or twice daily, maximum 200 mg) may be used in patients with mild fluid retention 1
• Metolazone (2.5 mg daily, maximum 20 mg) is particularly effective when added to loop diuretics for enhanced sodium excretion in resistant cases 1

Sequential Nephron Blockade for Resistant Hypernatremia

For patients who don't respond adequately to loop diuretics alone:

• Addition of a thiazide diuretic (e.g., metolazone) to a loop diuretic creates sequential nephron blockade, significantly enhancing sodium excretion 1
• This combination should be reserved for patients who don't respond to moderate or high-dose loop diuretics alone, as it significantly increases risk of electrolyte abnormalities 1

Administration Considerations

Oral Administration

• Start with low doses and titrate up until urine output increases and weight decreases (typically 0.5-1.0 kg daily) 1
• May require twice-daily dosing to maintain active diuresis 1

Intravenous Administration (for severe cases)

• For severe hypernatremia or when rapid correction is needed, IV administration may be necessary 1
• Initial IV dose should equal or exceed chronic oral daily dose 1
• Can be given as intermittent boluses or continuous infusion 1

Monitoring and Precautions

• Sodium correction rate should not exceed 8-10 mmol/L/day for chronic hypernatremia (>48 hours) to prevent osmotic demyelination syndrome 3
• Monitor serum electrolytes, urea nitrogen, and creatinine daily during active correction 1
• Watch for signs of volume depletion which can worsen renal function 1
• Excessive diuresis can lead to hypotension, azotemia, and impaired exercise tolerance 1

Special Considerations

• Patients may become unresponsive to high doses of diuretics if they consume large amounts of dietary sodium, take NSAIDs, or have significant impairment of renal function 1
• Diuretic resistance can be overcome by escalating loop diuretic dose, switching to IV administration, or combining different diuretic classes 1
• For extreme hypernatremia (sodium >190 mmol/L), more aggressive measures including hemodialysis may be necessary 3, 4

Adjunctive Therapies

• Free water replacement (oral or IV) is essential alongside diuretic therapy for hypernatremia correction 3
• In cases of diabetes insipidus causing hypernatremia, desmopressin (DDAVP) may be indicated rather than diuretics 3
• Vasopressin antagonists may be helpful in managing hyponatremia but are not indicated for hypernatremia 1