A serotonin antagonist, or serotonin receptor antagonist, is a drug used to inhibit the action of serotonin and serotonergic drugs at serotonin (5-HT) receptors.

Types

5-HT2A antagonists

Antagonists of the 5-HT2A receptor are sometimes used as atypical antipsychotics (contrast with typical antipsychotics, which are purely dopamine antagonists). They include, but are not limited to:

5-HT2A/2C antagonists

5-HT3 antagonists

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, but are not limited to: Other 5-HT3 antagonists have been considered for use in the treatment of irritable bowel syndrome: Also, the antidepressant mirtazapine acts as a 5-HT3 antagonist.

Non-selective 5-HT antagonists

Although some non-selective serotonin antagonists may have a particular affinity for a specific 5-HT receptor (and thus may be listed below e.g., methysergide), they still may also possess a generalised non-selective action. They include, but are not limited to:

Antihistamines with antiserotonergic activity

Others