A Case of Serotonin Syndrome Caused by Combination Therapy with Tapentadol and a Selective Serotonin Reuptake Inhibitor

ABSTRACT

Tapentadol was developed from tramadol by reducing its inhibitory effects on serotonin reuptake. In the present study, tapentadol was administered to a 49-year-old female esophageal cancer patient receiving a selective serotonin reuptake inhibitor (SSRI). On the day of administration, akathisia, nausea, dizziness, and insomnia developed. On the following day, she was diagnosed with serotonin syndrome, accompanied by fever, perspiration, myoclonic jerks mainly affecting the upper limbs, tremor of the extremities, and tachycardia. The diagnosis was made using three criteria. The symptoms disappeared immediately after discontinuation of tapentadol administration and initiation of benzodiazepine treatment. In Japan, tapentadol is an opioid analgesic for cancer pain management. If it is combined with an antidepressant, follow-up care is needed in consideration of serotonin syndrome.