Desmopressin (DDAVP) Does Not Increase Sodium Levels
Desmopressin (DDAVP) does not increase sodium levels; rather, it can cause hyponatremia (low sodium) by promoting water retention. 1
Mechanism of Action and Effects on Sodium
- Desmopressin is a synthetic analogue of antidiuretic hormone (ADH) vasopressin that decreases urine production at night when taken at bedtime 2
- It works by increasing water reabsorption in the kidneys, which can lead to decreased serum sodium concentration rather than increasing it 2
- The antidiuretic activity of desmopressin causes water retention, which can dilute serum sodium levels, potentially leading to hyponatremia 1
Risk of Hyponatremia
- Hyponatremia is a well-documented adverse effect of desmopressin therapy 3
- The FDA label specifically warns about the risk of hyponatremia with desmopressin use 1
- Water intoxication leading to hyponatremia and seizures is a rare but serious side effect of desmopressin therapy 2
- Patients taking desmopressin should limit fluid intake to prevent hyponatremia 1
Monitoring Recommendations
- Serum electrolyte levels, particularly sodium, should be monitored in patients taking desmopressin 4
- More frequent sodium monitoring is required when desmopressin is used concomitantly with medications that may increase the risk of hyponatremia (e.g., tricyclic antidepressants, SSRIs, NSAIDs, thiazide diuretics) 1
- Monitoring is especially important during intercurrent illnesses that might affect hydration status or alter drug absorption 2
- Recent research has explored capillary blood sodium monitoring as a potential way to enhance safety of desmopressin use, particularly in older patients 5
Special Considerations
- Discontinuing desmopressin in a patient with desmopressin-induced hyponatremia can lead to rapid correction of serum sodium and potential neurological injury 3
- Some research suggests continuing desmopressin while correcting hyponatremia with hypertonic saline may prevent overcorrection and lead to better outcomes 3, 6
- Patients with heart failure or uncontrolled hypertension may be at increased risk for fluid retention with desmopressin 1
- The risk of hyponatremia may vary by formulation, with some evidence suggesting better sodium control with oral disintegrating tablets compared to intranasal formulations 7
Clinical Implications
- Patients using desmopressin should be advised to limit fluid intake, particularly in the evening, to reduce the risk of hyponatremia 2, 1
- A general recommendation is evening fluid intake of 200 ml (6 ounces) or less and no drinking until morning 2
- Polydipsia (excessive drinking) is a contraindication to desmopressin treatment 2
- Healthcare providers should educate patients about the signs and symptoms of hyponatremia and when to seek medical attention 1