What are the side effects of metoclopramide?

Side Effects of Metoclopramide

Metoclopramide can cause serious neurological side effects including tardive dyskinesia, which may be irreversible, especially with long-term use beyond 12 weeks or in elderly patients. 1

Neurological Side Effects

• Tardive dyskinesia: Characterized by involuntary, repetitive movements primarily affecting the face and tongue. Risk increases with longer duration of treatment, higher doses, advanced age (especially in women), and in patients with diabetes 1, 2
• Acute dystonic reactions: Uncontrolled spasms of face, neck, and body muscles causing abnormal movements and postures. These typically occur within the first 2 days of treatment and are more common in children and adults under 30 1, 3
• Parkinsonism: Symptoms include slight shaking, body stiffness, and trouble with movement or balance. Pre-existing Parkinson's disease may worsen with metoclopramide use 1, 4
• Neuroleptic Malignant Syndrome (NMS): A rare but potentially fatal condition characterized by high fever, muscle rigidity, altered mental status, irregular heartbeat, and increased sweating 1

Psychiatric Side Effects

• Depression and suicidal ideation: Some patients may experience depression and thoughts about self-harm or suicide 1
• Confusion and anxiety: Mental status changes can occur, particularly when the medication is administered too rapidly 1
• Restlessness and sleep disturbances: Common side effects include feeling restless and having trouble sleeping 1

Other Side Effects

• Sedation: Drowsiness, tiredness, dizziness, and exhaustion are common 1
• Headache: Frequently reported side effect 1
• Endocrine effects: Can cause hyperprolactinemia due to its dopamine-blocking properties 5
• Gastrointestinal effects: May cause gastrointestinal upset 6

Risk Factors for Adverse Effects

• Duration of treatment: Risk increases significantly with treatment beyond 12 weeks 1
• Age: Elderly patients are at higher risk, particularly for tardive dyskinesia 2, 7
• Gender: Women appear to be more susceptible to tardive dyskinesia 2
• Pre-existing conditions: Patients with diabetes, Parkinson's disease, depression, kidney problems, or liver disease are at increased risk 1
• Medication interactions: Interactions with other medications that affect the central nervous system can increase side effects 1

Important Warnings and Precautions

• FDA black box warning: Metoclopramide should not be used for more than 12 weeks due to the risk of tardive dyskinesia 5
• Monitoring: Patients should be regularly monitored for the development of movement disorders 6
• Alcohol: Patients should avoid alcohol while taking metoclopramide as it may worsen side effects, particularly sedation 1
• Driving and operating machinery: Patients should not drive or operate dangerous machinery until they know how metoclopramide affects them 1

Alternative Treatments

For patients requiring long-term therapy for conditions like gastroparesis or intestinal dysmotility, alternatives to consider include:

• Domperidone: A peripheral D2 dopamine receptor antagonist that does not readily cross the blood-brain barrier, but requires QTc monitoring due to cardiac risks 6, 8
• Erythromycin or azithromycin: Motilin agonists that can improve gastric emptying, though tachyphylaxis limits long-term use 6, 8
• Prucalopride: A selective 5-HT4 receptor agonist for constipation without the cardiac risks of older prokinetics 6, 8

Remember that metoclopramide should be discontinued immediately if signs of tardive dyskinesia, acute dystonic reactions, or other serious neurological side effects develop 1.