Serotonin syndrome is a rare adverse reaction induced by
serotonergic drugs. Most instances of the syndrome occur in the context of a serotonergic
drug overdose and the combined use of
monoamine oxidase inhibitors and other related drugs. We report a case of
serotonin syndrome caused by
duloxetine alone in an elderly Asian woman and review the literature. A 69-year-old woman was admitted to the hospital due to two months of irritability and reduced energy. She was diagnosed with
depressive disorder in the outpatient department and took
sertraline 75mg for one month, but there was no significant improvement of symptoms. After admission,
sertraline was switched to
duloxetine. After taking
duloxetine 60mg, the patient developed
confusion, inducible clonus, diaphoresis,
tremor,
hyperreflexia, and increased body temperature and blood pressure. Reviewing her history of
drug exposure, physical examination, and associated laboratory tests, we ruled out other possible diseases and established a
serotonin syndrome diagnosis. The symptoms and signs associated with
serotonin syndrome disappeared within two days
after treatments with hydration and
diazepam and the withdrawal of
duloxetine. Physicians should be watchful for
serotonin syndrome, a rare, but in severe cases life-threatening,
adverse drug reaction. It may occur with
duloxetine monotherapy even at therapeutic doses.