What is the recommended rate and timeline for correcting hypernatremia?

• A. 5 mEq/L per hour
• B. No more than 1 mEq/L per hour with 50% correction in 24-35 hr and complete correction in 3-7d
• C. 0.1 mEq/L per hour
• D. 2 mEq/L per hour

Answer: (B)

Correcting hypernatremia must be gradual because brain cells adapt to high osmolality and rapid shifts can cause dangerous cerebral edema. The safest plan sets a ceiling on how fast the sodium can fall and uses a staged correction over days rather than hours.

No more than about 1 mEq/L per hour is allowed, and a practical target is to reduce roughly half of the total sodium deficit within the first 24 to 35 hours, then finish correction over about 3 to 7 days. This approach balances the need to reverse the hypernatremia with the risk of osmotic shifts affecting the brain.

For example, if the serum Na is 160 mEq/L and your target is 140 mEq/L, the deficit is 20 mEq/L. Aiming for about 10 mEq/L drop in the first day or so would meet the guideline, with the remainder achieved gradually over the following days, provided the patient’s volume status and underlying cause are corrected appropriately.