ABSTRACT
A TOXIC REACTION: Prevalence of the serotonin syndrome is increasing and can be fatal. The physiopathological hypothesis is principally supported by excess stimulation of the central (5HT1a) serotonin receptors. There are various serotonin drugs and associations implied. Monoamine oxidase inhibitors appear to be the major culprits. RECENTLY REVISED CLINICAL DIAGNOSIS FACTORS: The classical triad of neuropsychiatric, neuromuscular and neurovegetative symptoms, described in 1991 by Sternbach, has recently been modified. The syndrome is however protein-like and differential diagnosis remains the neuroleptic malignant syndrome. FIRST-LINE THERAPEUTIC MEASURES: Prevention of the syndrome and its early discovery are essential. Withdrawal of the imputable drugs often resolves the symptoms within 24 hours. Symptomatic and supportive care remains the pillar to treatment. ORIENTATION TOWARDS SPECIFIC TREATMENTS: Several non-selective anti-serotonin treatments have been tested without much success. In the absence of prospective studies, current therapeutic strategies rely on case reports demonstrating the relative efficacy of cyproheptadine and chlorpromazine. The proposed treatment, as soon as severe or persisting symptoms are observed, is administration of 8 to 30 mg cyproheptadine per os, and in the case of failure or contraindication, followed by 50 to 100 mg of intramuscular chlorpromazine, renewed when necessary.
