What are the proper usage and precautions for Reglan (metoclopramide)?

Proper Usage and Precautions for Reglan (Metoclopramide)

Metoclopramide (Reglan) should be used for short-term treatment (generally less than 12 weeks) due to the risk of serious neurological side effects, particularly tardive dyskinesia, with long-term use. 1, 2

Approved Indications

• Diabetic gastroparesis: Metoclopramide improves gastric motility and is indicated for relief of symptoms associated with diabetic gastric stasis 1
• Prevention of chemotherapy-induced nausea and vomiting: Particularly effective when administered intravenously before and during chemotherapy 1
• Prevention of postoperative nausea and vomiting: Typically administered intramuscularly near the end of surgery 1
• Facilitation of small bowel intubation: Aids in radiological examinations by improving gastric emptying 1
• Management of opioid-induced nausea: Can be used as an antiemetic agent for persistent nausea related to opioid therapy 3

Dosing Considerations

• Standard adult dosing: 10 mg orally, 3-4 times daily before meals and at bedtime 1
• Renal impairment: For patients with creatinine clearance below 40 mL/min, initiate at approximately half the recommended dosage 1
• Hepatic impairment: Minimal dose adjustment needed for liver disease when renal function is normal 1
• Duration: Oral preparations are recommended for 4-12 weeks of therapy; parenteral use should be limited to 1-2 days 4

Major Precautions and Contraindications

• Tardive dyskinesia risk: The FDA has issued warnings about serious adverse effects with prolonged use (>12 weeks), including tardive dyskinesia 5, 2

  • Recent research suggests the risk is lower than previously estimated, approximately 0.1% per 1000 patient-years rather than the 1-10% previously suggested 2
  • High-risk groups include elderly females, diabetics, patients with renal or hepatic impairment, and those on concomitant antipsychotic therapy 2

• Extrapyramidal symptoms: May cause acute dystonic reactions, parkinsonism, or akathisia, especially with high doses 6

• Contraindications:

  • History of tardive dyskinesia or dystonic reaction to metoclopramide 1
  • Seizure disorders (use with caution) 5
  • GI bleeding or obstruction 5
  • Pheochromocytoma (may release catecholamines) 1

Drug Interactions

• Anticholinergic drugs and narcotic analgesics: Antagonize the effects of metoclopramide on gastrointestinal motility 1
• Sedatives, hypnotics, narcotics, or tranquilizers: Additive sedative effects can occur 1
• Monoamine oxidase inhibitors: Use cautiously due to potential catecholamine release 1
• Insulin: May require dosage adjustment as metoclopramide accelerates gastric emptying and may affect absorption of glucose 1
• Oral medications: May alter absorption rates (decreased for drugs absorbed in stomach, increased for those absorbed in small intestine) 1

Monitoring and Side Effect Management

• Common side effects: Restlessness, drowsiness, fatigue, and lassitude 4
• Neurological monitoring: Regular assessment for signs of extrapyramidal symptoms, especially with long-term use 7
• For acute dystonic reactions: Administer 50 mg diphenhydramine intramuscularly to manage symptoms 1

Special Populations

• Elderly patients: Use with caution due to increased risk of tardive dyskinesia and other extrapyramidal symptoms 8
• Pregnancy: Consider risks and benefits; use only if clearly needed 1
• Hypertensive patients: Use with caution as metoclopramide may release catecholamines 1
• Patients with heart failure or cirrhosis: Monitor for fluid retention and volume overload due to transient increase in plasma aldosterone 1

Alternative Medications

• Domperidone: A peripheral D2 dopamine receptor antagonist that can be considered as an alternative for long-term therapy, but requires QTc monitoring due to cardiac risks 7
• Erythromycin or azithromycin: Motilin agonists that can improve gastric emptying, though tachyphylaxis limits long-term use 7
• Prucalopride: A selective 5-HT4 receptor agonist for constipation without the cardiac risks of older prokinetics 7

Administration Considerations

• Intravenous administration: Should be made slowly over 1-2 minutes for 10 mg doses to avoid transient anxiety and restlessness 1
• Dilution for higher doses: For doses exceeding 10 mg, dilute in 50 mL of parenteral solution, preferably normal saline 1
• Post-surgical use: Consider theoretical risk of increased pressure on suture lines following gut anastomosis 1