Sustained serotonin syndrome in a treatment-resistant depressed patient during maintenance treatment with combination of three serotonergic agents


  • Stavroula Theodoropoulou Pasteur 5, Athens 11521
  • Vasiliki Triantafyllou
  • Georgios Konstantakopoulos
  • Evangelia Bellou
  • Athanasios Yalouris



Serotonin syndrome (SS) is a relatively rare but potentially life-threatening  condition caused by agents affecting serotonin (5-Hydroxytryptamine; 5-HT) metabolism or acting as direct 5-HT receptor agonists or both.15-HT is a monoamine neurotransmitter synthesized from the amino acid tryptophan. In the central nervous system,it regulates functions such as mood, appetite, sexual activity, sleep and some cognitive functions. Peripherally, 5-HT promotes  platelet  aggregation and also affects peristalsis and vascular tone2,3. A large number of agents, such as antidepressants (monoamine oxidase inhibitors-MAOIs, tricyclic antidepressants-TCAs, selective serotonin reuptake inhibitors-SSRIs, serotonin-norepinephrine reuptake inhibitors-SNRIs, buspirone, St. John’s wort),antibiotics (linezolid), antiemetics (ondansetron) antimigraine medications (sumatriptan), drugs of abuse (amphetamine, cocaine, LSD, ecstasy), herbal supplements and others have been associated with SS1.The vast majority of antidepressants can cause SS either by direct receptor agonism (buspirone), through decreased reuptake of 5-HT(SSRIs, SNRIs, TCAs) or  decreased  5-HT breakdown(MAOIs)1. Lithium is used in combination with other antidepressants and has also been implicated in the development of SS4,5.