Sodium Deficit in Hyponatremia

Male: Sodium Replacement (mmol) = [142 - Serum Sodium (mmol/L)] × Current Weight (kg) × 0.6

Female: Sodium Replacement (mmol) = [142 - Serum Sodium (mmol/L)] × Current Weight (kg) × 0.5

Clinically, it is important not to rely solely on any formula to determine sodium replacement; the formula serves only as an estimate for safe dosing. Additionally, be cautious of hypervolemia during fluid replacement, which can be very dangerous for those with heart failure.

The maximum correction rate for hyponatremia: 8-10 mmol/L/d; if symptomatic, correct at 1-2 mmol/L/h until symptoms resolve, with a maximum correction of 12 mmol/L in 24 hours. One liter of 3% NaCl contains 513 mmol Na+, and one liter of 0.9% NaCl (NS) contains 154 mmol Na+.