Multiple drug interactions - induced serotonin syndrome: a case report.

Serotonin syndrome is a potentially life-threatening disorder of excessive serotoninergic activity often due to drug interactions. We report a case of serotonin syndrome induced by pharmacokinetic and pharmacodynamic interactions between three different selective serotonin-reuptake inhibitors (SSRI) and possibly ciprofloxacin. Extreme caution is necessary in patients treated with serotonin-reuptake inhibitors who need to be switched to another antidepressant or when they require the addition of concomitant drugs, especially serotoninergic drugs and isoenzimes of cytochrome P450 inhibitors.