A 44-year-old woman seen in an emergency for convulsions one month after 3 mg/day of risperidone was added to her treatment in 2007 was found to have a blood glucose level of 2,089 mg/dl. She was diagnosed with hyperosmolar nonketotic diabetic coma and given insulin, and risperidone was discontinued. After discharge, her diabetes was controlled by diet alone.
Four months after discharge, her delusions relapsed and perospirone hydrochloride was started. Six mg/day of aripiprazole was added 5 months after perospirone hydrochloride was started. She redeveloped severe diabetes mellitus within a month of aripiprazole initiation, although she maintained HbA₁c of 5% when treated with perospirone hydrochloride alone. On admission in 2008, she required treatment with insulin (30 units/day), but her insulin requirements fell shortly after aripiprazole was stopped. She did not require insulin therapy on discharge.
Aripiprazole, a relatively new antipsychotic drug approved for treating schizophrenia, is considered to have the fewest side effects of all atypical antipsychotics, but our case suggests the importantance of carefully monitoring blood glucose when prescribing atypical antipsychotics such as aripiprazole.