title: Cyclophosphamide-induced severe acute hyponatremic encephalopathy in patients with breast cancer: report of two cases.
abstract: BACKGROUND
  Cyclophosphamide is an alkylating agent widely used in antineoplastic and immunosuppressive therapies. Symptomatic hyponatremia can be a rare but life-threatening complication in patients treated with cyclophosphamide.
  
  
  METHODS
  We report 2 patients who presented with severe acute hyponatremic encephalopathy after receiving their first cycles of a low-dose cyclophosphamide-containing regimen for breast cancer. In case 1, a 58-year-old female received the combination of docetaxel and cyclophosphamide, and in case 2, a 56-year-old female received the combination of doxorubicin and cyclophosphamide. Both patients recovered after correction of their serum sodium concentration without neurological deficits. Future cycles of chemotherapy were well tolerated without recurrence of hyponatremia after cyclophosphamide was discontinued from the respective regimens.
  
  
  CONCLUSIONS
  Clinicians must always keep in mind that acute hyponatremic encephalopathy can be induced by low-dose cyclophosphamide.
authors.affiliation: Departments of Pharmacy and Western Regional Medical Center, Cancer Treatment Centers of America, Goodyear, Ariz., USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Baker
authors.affiliation: Departments of Medical Oncology, Western Regional Medical Center, Cancer Treatment Centers of America, Goodyear, Ariz., USA ; Drexel University College of Medicine, Philadelphia, Pa., USA.
authors.forename: Maurie
authors.initials: M
authors.lastname: Markman
authors.affiliation: Departments of Medical Oncology, Western Regional Medical Center, Cancer Treatment Centers of America, Goodyear, Ariz., USA.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Niu
keywords: Chemotherapy; Cyclophosphamide; Encephalopathy; Hyponatremia; Syndrome of inappropriate antidiuretic hormone secretion