Serotonin syndrome after a massive overdose of controlled-release paroxetine.

Background: Serotonin syndrome is a condition resulting from an overabundance of serotonin at postsynaptic receptors. The syndrome usually responds to cyproheptadine and benzodiazepines. However, some patients do not respond to conventional treatment.

Objective: The authors report on the history and management of a patient, a 55-year-old man, who had taken a massive overdose of paroxetine, controlled-release.

Method: The authors present a case report of history and treatment. Paroxetine levels were measured on Days 3 and 7 after admission, with rising values of the drug. The patient received a course of cyproheptadine and lorazepam, to which he was unresponsive, and he was transferred to the Medical Intensive Care Unit for heavy sedation.

Results: The patient had initially presented with minor symptoms of serotonin syndrome, but these quickly progressed in severity, and he eventually died from resulting complications: a pulmonary embolism 9 days after admission, despite appropriate prophylaxis with enoxaparin.

Conclusion: The authors are the first to report on a paroxetine overdose of this magnitude, and they provide one of the few reports on a prolonged course of serotonin syndrome that was unresponsive to standard treatment.