Metoclopramide (Reglan): Usage Guidelines and Side Effects
Metoclopramide (Reglan) is primarily indicated for gastroparesis treatment as a first-line therapy, but carries significant risk of neurological side effects including tardive dyskinesia, limiting its recommended use to no more than 12 weeks. 1
Indications and Mechanism of Action
Metoclopramide is a dopamine (D2) receptor antagonist with prokinetic properties that:
- Is the only FDA-approved medication for gastroparesis 1
- Functions as a prokinetic agent that stimulates gastric emptying 2
- Has antiemetic properties, making it useful for treating nausea and vomiting 2
- Improves gastric motility by enhancing acetylcholine release from enteric nerves 2
Dosage and Administration
- Standard dosing: 10 mg three times daily before meals 1
- Initial therapeutic trial should last at least 4 weeks 1
- Maximum duration of therapy should not exceed 12 weeks due to risk of tardive dyskinesia 3
- Available in oral, intravenous (IV), and intramuscular (IM) formulations 3
Major Side Effects and Safety Concerns
Neurological Effects
Extrapyramidal symptoms: Can occur early in treatment course 4
- Acute dystonia (involuntary muscle contractions)
- Akathisia (restlessness, inability to remain still)
- Parkinsonism (tremor, rigidity, bradykinesia)
Tardive dyskinesia: Risk increases with:
Other Common Side Effects
- Sedation, drowsiness, fatigue 3
- Restlessness and anxiety 3
- Confusion and dizziness 3
- Depression and potential suicidal thoughts 3
Contraindications and Precautions
Metoclopramide should be avoided in patients with:
- History of tardive dyskinesia or dystonic reactions 3
- Parkinson's disease (may worsen symptoms) 3
- Seizure disorders 3
- Pheochromocytoma 2
Drug Interactions
Exercise caution when combining metoclopramide with:
- Antipsychotics (increased risk of extrapyramidal symptoms) 6
- MAO inhibitors 3
- Sedatives, sleep medications, and narcotics (increased sedation) 3
- Insulin (may require dose adjustment) 3
Monitoring Recommendations
- Assess for neurological side effects at each visit
- Monitor for signs of tardive dyskinesia (involuntary movements of face, tongue, limbs)
- Discontinue immediately if neurological side effects occur
- Consider QTc monitoring with long-term use 2
Alternative Treatments
When metoclopramide is contraindicated or poorly tolerated:
- Erythromycin (motilin agonist) as second-line therapy 1
- Domperidone (not FDA-approved in US, available through special access) 2
- Prucalopride (5-HT4 receptor agonist) shows promise with potentially fewer neurological side effects 1
Clinical Pearls
- Despite its effectiveness, metoclopramide accounts for nearly one-third of all drug-induced movement disorders 4
- Even short-term, low-dose treatment can occasionally cause long-lasting adverse effects 7
- Risk of tardive dyskinesia increases significantly with treatment beyond 12 weeks 3
- For gastroparesis in diabetic patients, optimizing glycemic control is essential alongside prokinetic therapy 1
Metoclopramide remains valuable for short-term treatment of gastroparesis and as an antiemetic, but the risk-benefit ratio must be carefully considered, particularly for extended use beyond the recommended 12-week maximum duration.