What is the appropriate dose of metoclopramide (Reglan) for an adult patient with no contraindications?

Metoclopramide Dosing for Adults Without Contraindications

For an adult patient with no contraindications, the appropriate dose of metoclopramide is 10 mg administered orally or intravenously, given 3-4 times daily, with treatment strictly limited to a maximum of 5 days and a maximum daily dose of 30 mg to minimize serious neurological complications. 1, 2, 3

Standard Dosing by Clinical Indication

Nausea and Vomiting (General)

• 10 mg orally or IV, administered 3-4 times daily 1, 2
• Administer 20-30 minutes before meals when used for gastroparesis-related symptoms 2
• For acute nausea/vomiting, give every 6-8 hours as needed 2

Diabetic Gastroparesis

• 10 mg orally 30 minutes before each meal and at bedtime (4 times daily) 1
• If severe symptoms are present, initiate therapy with IV or IM administration at 10 mg slowly over 1-2 minutes 3
• May require up to 10 days of parenteral therapy before transitioning to oral administration 3

Chemotherapy-Induced Nausea and Vomiting

• For highly emetogenic regimens (cisplatin, dacarbazine): 2 mg/kg IV infused over at least 15 minutes 3
• For less emetogenic regimens: 1 mg/kg per dose may be adequate 3
• Administer 30 minutes before chemotherapy, repeat every 2 hours for 2 doses, then every 3 hours for 3 doses 3

Postoperative Nausea and Vomiting

• 10 mg IM near the end of surgery (20 mg may be used in select cases) 3

Critical Safety Parameters and Duration Limits

The European Medicines Agency mandates restricting metoclopramide to short-term use of maximum 5 days and a maximum daily dose of 30 mg to minimize the risk of extrapyramidal disorders and tardive dyskinesia. 1, 2

Key Safety Considerations:

• Risk of tardive dyskinesia increases with chronic use, particularly in elderly patients 2
• Extrapyramidal symptoms can occur even after a single 10 mg dose 4
• Long-lasting adverse effects (tremors, involuntary movements, anxiety) have been reported after short-term low-dose use (as little as 30 mg total over several days) 5
• If acute dystonic reactions occur, administer 50 mg diphenhydramine IM 3

Dose Adjustments for Special Circumstances

Renal Impairment

• For creatinine clearance <40 mL/min: initiate at approximately one-half the recommended dose 1, 6, 3
• Metoclopramide is excreted principally through the kidneys 3
• May increase or decrease dosage based on clinical efficacy and safety 3

Hepatic Impairment

• Use with caution in severe hepatic impairment 1
• Metoclopramide undergoes minimal hepatic metabolism except for simple conjugation 3
• Safe use has been described in patients with advanced liver disease whose renal function was normal 3

Elderly or Frail Patients

• Consider starting with lower doses (e.g., 5 mg) 7
• Higher risk of adverse effects including extrapyramidal symptoms 1

Administration Routes

Oral Administration

• Standard tablets: 5-20 mg per dose 1
• Administer 20-30 minutes before meals for optimal effect 2

Intravenous Administration

• Doses up to 10 mg: administer slowly over 1-2 minutes 3
• Doses >10 mg: dilute in 50 mL parenteral solution and infuse over at least 15 minutes 3
• Preferred diluent is normal saline 3

Intramuscular Administration

• 10 mg IM is standard dose 3
• Commonly used for postoperative nausea/vomiting 3

Common Pitfalls to Avoid

• Never exceed 5 days of treatment duration for standard indications 1, 2
• Never exceed 30 mg total daily dose 1, 2
• Do not use in patients with seizure disorders, pheochromocytoma, GI bleeding, or GI obstruction 2
• Avoid in Parkinson's disease or dementia with Lewy bodies due to high risk of extrapyramidal symptoms 2
• Monitor QT interval with repeated doses, as metoclopramide can prolong QTc 6
• In diabetic patients, may require adjustment of insulin or sulfonylurea doses due to effects on gastric emptying 6