[Serotonin syndrome in a patient with small cell lung cancer]

The patient was a 67-year-old male who had been treated for several years with 150 mg fluvoxamine maleate due to depression. He visited our hospital with primary symptoms of swelling of the right upper extremity and dyspnea in August, XXXX. As a result of examinations, he was diagnosed with stage IIIB extended small cell lung cancer(T4N3M0). One course of carboplatin/etoposide(CBDCA/VP-16)therapy was started on October 1. Since the tumor size was reduced, thoracic effusion disappeared, and superior vena cava syndrome was alleviated, the therapy was changed to cisplatin/irinotecan (CDDP/CPT-11)on October 23, and the 3rd course was initiated on November 22. Anxiety and tremor appeared on the 4th day of the 3rd course and because they were exacerbated, and myoclonus appeared, a diagnosis of serotonin syndrome was made on the 38th day, and the administration of fluvoxamine maleate was discontinued. The symptoms were alleviated after the discontinuation, and the 4th course could be implemented. In this patient, serotonin syndrome was considered to have been induced by serotonin secretion promoted by the CDDP administration, and by serotonin in the brain increasing abnormally due to the SSRI.