Serotonin antagonist

A serotonin antagonist is a drug used to inhibit the action at serotonin (5-HT) receptors.

Antagonists of the 5-HT_2A receptor are sometimes used as atypical antipsychotics (contrast with typical antipsychotics, which are purely dopamine antagonists). They include:

Another subclass consists of drugs selectively acting at the 5-HT₃ receptors, and thus are known as 5-HT₃ antagonists. They are efficacious in treating chemotherapy-induced emesis and postoperative nausea and vomiting. They include:

Other 5-HT₃ antagonists are used for the treatment of irritable bowel syndrome:

Also, the antidepressant mirtazapine acts as a 5-HT<sub3>3 _antagonist.

_{Please note, that although some non-selective serotonin antagonists may have an particular affinity for a specific 5-HT receptor (and thus may be listed above e.g. methysergide), they still may also possess a generalised non-selective action.}

...
Wikipedia