Wikipedia
Symptoms caused by an excess of serotonin in the central nervous system
Summary
Serotonin syndrome (SS) consists of a group of symptoms that may occur with the use of certain serotonergic medications or drugs. The symptoms can range from mild to severe, and are potentially fatal. Symptoms in mild cases include high blood pressure and a fast heart rate, usually without a fever. Symptoms in moderate cases include high body temperature, agitation, overactive reflexes, tremor, sweating, dilated pupils, and diarrhea. In severe cases, body temperature can increase to greater than 41.1 °C (106.0 °F). Complications may include seizures and extensive muscle breakdown.