American Board of Psychiatry and Neurology (ABPN) Practice Exam 2025 - Free ABPN Practice Questions and Study Guide

Mirtazapine is known for its anti-nausea effects, which can be attributed to its action as an antagonist at the serotonin receptor 3 (5-HT3). The 5-HT3 receptor is involved in the emetic pathway, particularly in the gastrointestinal tract and the central nervous system, where its activation can lead to nausea and vomiting. By blocking this receptor, mirtazapine can reduce the sensation of nausea, making it effective in alleviating these symptoms.

The role of other mechanisms mentioned, such as 5-HT2 antagonism and α2 antagonism, while relevant to the overall pharmacological profile of mirtazapine, do not specifically account for the decrease in nausea. The 5-HT2 system is more closely associated with mood regulation and certain anxiety responses, while α2 antagonism relates to the noradrenergic and adrenergic systems, influencing sedation and appetite stimulation but not primarily nausea control. Therefore, the action of mirtazapine at the 5-HT3 receptor is critical for its effectiveness in managing nausea.