Metoclopramide and homicidal ideation: a case report and literature review.

Metoclopramide is an anti-emetic and gastrointestinal pro-motility agent associated with well-known neuropsychiatric adverse effects, such as dyskinesia, akathisia, and depression. It has never been reported to be associated with homicidal ideation. The authors review the literature on metoclopramide-induced adverse neuropsychiatric reactions and the mechanisms by which these may occur. The authors present a case report of a patient who developed anxiety, agitation, suicidal and homicidal ideation following brief exposure to metoclopramide. The adverse effects of agitation and homicidal ideation were temporally related to the starting and stopping of metoclopramide. The patient subsequently developed agitation without homicidal ideation when given a serotonergic antidepressant a week later, suggesting that serotonin handling may have played a significant role in causing the patient's symptoms. Although metoclopramide is well-known for its side effects related to dopamine blockade, its action at 5-HT₃ and 5-HT₄ receptors may also be clinically significant in the genesis of neuropsychiatric side effects, especially related to mood and behavior.