Metoclopramide-induced Serotonin Syndrome

Area of Science:

• Pharmacology
• Neuroscience
• Clinical Toxicology

Background:

• Mirtazapine is a commonly prescribed medication for bipolar disorder.
• Metoclopramide is frequently used for various gastrointestinal symptoms.
• Serotonergic agents are widely used in psychiatric and medical practice.

Observation:

• A patient on mirtazapine developed mydriasis, diaphoresis, myoclonus, and muscle rigidity after metoclopramide administration.
• The patient's clinical presentation met the Hunter criteria for serotonin syndrome (SS).

Findings:

• Metoclopramide, though not commonly recognized for this effect, can induce serotonin syndrome.
• Symptoms resolved with lorazepam, cyproheptadine, and a reduced mirtazapine dose, confirming the diagnosis.

Implications:

• This case highlights the potential for metoclopramide to cause serotonin syndrome.
• Awareness of drug-drug interactions is crucial to prevent potentially fatal serotonin syndrome.
• Careful patient monitoring is recommended when combining serotonergic agents with other medications.