Medications for Hypernatremia
The primary treatment for hypernatremia is not medication-based but rather fluid replacement with hypotonic solutions (5% dextrose in water or 0.45% saline), with desmopressin reserved specifically for cases of diabetes insipidus. 1, 2, 3
Treatment Approach Based on Underlying Cause
Fluid Replacement (First-Line Treatment)
Hypotonic fluid replacement is the cornerstone of hypernatremia management, using either 5% dextrose in water (D5W) or 0.45% normal saline administered intravenously 1, 2, 3
For patients who can tolerate oral intake, free water administration via nasogastric tube is an effective alternative to intravenous hypotonic fluids 1
The rate of correction must be carefully controlled: chronic hypernatremia (>48 hours) should not be reduced by more than 8-10 mmol/L per day to prevent osmotic demyelination syndrome 3
For acute hypernatremia (<24 hours), more rapid correction is permissible, and hemodialysis can be considered for severe cases 3
Desmopressin (Medication-Specific Treatment)
Desmopressin (Minirin) is indicated specifically for diabetes insipidus-related hypernatremia, not for other causes of hypernatremia 1, 3
In the case of combined hyperglycemia and severe hypernatremia, desmopressin can be used alongside free water replacement to correct severe free water deficits 1
Desmopressin works by reducing renal free water losses in patients with central or nephrogenic diabetes insipidus 3
Correction Rate Guidelines and Monitoring
Rate of Correction
For chronic hypernatremia (>48 hours duration): maximum correction of 8-10 mmol/L per 24 hours 3
For acute hypernatremia (<24 hours): more rapid correction is safe, though close monitoring remains essential 3
Too rapid correction can cause cerebral edema and neurological deterioration, particularly in chronic cases 3, 4
Monitoring Requirements
Close laboratory monitoring of serum sodium levels is mandatory during treatment, with frequent checks to ensure correction rate stays within safe limits 3
When initiating renal replacement therapy in patients with chronic hypernatremia, special attention must be paid to avoid rapid sodium drops 3
Special Clinical Scenarios
Combined Hyperglycemia and Hypernatremia
In cases of diabetic ketoacidosis or hyperglycemic hyperosmolar state with severe hypernatremia (sodium >190 mEq/L after correction), combination therapy with D5W, Ringer's lactate, free water via NG tube, and IV desmopressin has been shown effective 1
Calculate corrected sodium in hyperglycemic patients before determining treatment approach, as measured sodium may underestimate true severity 1
Volume Status Considerations
Assess volume status to guide fluid selection: hypovolemic patients may require initial isotonic resuscitation before transitioning to hypotonic fluids 2, 3
In cases of salt intoxication, diuretics must be added to hypotonic fluid replacement to prevent pulmonary edema 4
Common Pitfalls to Avoid
Avoid overly rapid correction (>10-12 mmol/L per day in chronic hypernatremia), which can cause osmotic demyelination syndrome 3
Do not use desmopressin for hypernatremia unrelated to diabetes insipidus, as it will not address the underlying pathophysiology 3
Inadequate water prescription in hospitalized patients is a common iatrogenic cause of hypernatremia and is preventable with appropriate fluid orders 5
Failing to address ongoing water losses while only replacing deficits will result in treatment failure 5