Excessive fluid intake when urine output is limited by the antidiuretic effect of desmopressin may lead to water intoxication with hyponatremia. Cases of hyponatremia have been reported from postmarketing experience in patients treated with desmopressin acetate. Unless properly diagnosed and treated, hyponatremia can be fatal.
All patients receiving desmopressin nasal spray solution should be observed for the following signs or symptoms associated with hyponatremia: headache, nausea/vomiting, decreased serum sodium, weight gain, restlessness, fatigue, lethargy, disorientation, depressed reflexes, loss appetite, irritability, muscle weakness, muscle spasms or cramps and abnormal mental status such as hallucinations, decreased consciousness, and confusion. Severe symptoms due to an extreme decrease in serum sodium and plasma osmolality may include one or a combination of the following: seizure, coma, and/or respiratory arrest.
In order to decrease the risk of water intoxication with hyponatremia, fluid restriction is recommended. Careful fluid intake restriction is particularly important in pediatric and geriatric patients because these patients are at greater risk of developing hyponatremia
[seeUse in Specific Populations (8.4,
8.5)].
More frequent monitoring of serum sodium levels is recommended in the following patients: those with conditions associated with fluid and electrolyte imbalance, such as cystic fibrosis, heart failure, renal disorders, habitual or psychogenic polydipsia or those taking concomitant drugs that may cause hyponatremia
[seeDrug Interactions (7.1)].
Desmopressin nasal spray solution is not an indicated formulation for the treatment of primary nocturnal enuresis due to a higher risk of hyponatremia and hyponatremic convulsions with the use of the nasal spray formulation compared to desmopressin tablets seen in postmarketing reports
[see
Indications and Usage(
1)].