Syndrome of inappropriate antidiuretic hormone associated with tolterodine therapy.
OBJECTIVE
To present a case of syndrome of inappropriate antidiuretic hormone (SIADH) associated with the use of tolterodine.


METHODS
An acute-care unit at a university hospital with a comprehensive program for elders.


METHODS
In this case report, we present a 99-year-old female who was admitted to our unit for suspected gastrointestinal bleeding who subsequently developed hyponatremia. After the initiation of tolterodine for urinary incontinence, the patient's sodium dropped to 121 mEq/L (from a usual baseline that ranged between 128 mEq/L and 134 mEq/L). Laboratory and urinary findings revealed a serum osmolality of 220 mOsm/kg, a urinary osmolality of 340 mOsm/kg, and a urinary sodium of 101 mmol/L, suggesting a euvolemic hyponatremic state consistent with SIADH. Tolterodine therapy was promptly discontinued, and patient sodium levels normalized.


CONCLUSIONS
Although the etiology of SIADH is often obscure and multifactorial, clinicians should be aware that it is a major cause of hyponatremia among hospitalized elderly patients, and drug therapies must always be evaluated to prevent further complications.
Bryan
Monique K
MK
Montefiore North Hospital, Bronx, NY, USA.
Nguyen
May T
MT
Hilas
Olga
O
D000369:Aged, 80 and over; D001559:Benzhydryl Compounds / Q000009:adverse effects* / Q000627:therapeutic use; D003408:Cresols / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis / Q000209:etiology; D007177:Inappropriate ADH Syndrome / Q000139:chemically induced* / Q000175:diagnosis; D018727:Muscarinic Antagonists / Q000009:adverse effects* / Q000627:therapeutic use; D010665:Phenylpropanolamine / Q000009:adverse effects* / Q000627:therapeutic use; D000068737:Tolterodine Tartrate; D014549:Urinary Incontinence / Q000188:drug therapy
D001559:Benzhydryl Compounds; D003408:Cresols; D018727:Muscarinic Antagonists; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate