What is the standard dosing of metoclopramide for adults?

Standard Dosing of Metoclopramide in Adults

The standard dose of metoclopramide for adults is 10 mg administered orally or intravenously three to four times daily for nausea and vomiting, 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

Dosing by Clinical Indication

Nausea and Vomiting (General)

• 10 mg orally or IV every 6-8 hours (three to four times daily), administered 20-30 minutes before meals 1, 2
• Alternative dosing: 10-20 mg orally three to four times daily for more severe symptoms 2
• Maximum duration: 5 days to prevent tardive dyskinesia and extrapyramidal effects 1, 2
• Maximum daily dose: 30 mg/day 1, 2

Diabetic Gastroparesis

• 10 mg administered 30 minutes before meals and at bedtime (four times daily) 1, 3
• For severe symptoms, initiate with 10 mg IV or IM slowly over 1-2 minutes, then transition to oral dosing once symptoms improve 3
• Up to 10 days of parenteral therapy may be required before oral administration can begin 3

Chemotherapy-Induced Nausea and Vomiting (High-Dose Protocol)

• 2 mg/kg IV for highly emetogenic drugs (cisplatin, dacarbazine) 3, 4
• 1 mg/kg IV for less emetogenic regimens 3
• Administer slowly over at least 15 minutes, 30 minutes before chemotherapy 3
• Repeat every 2 hours for two doses, then every 3 hours for three doses 3
• This high-dose protocol is supported by controlled trials showing superiority over placebo and other antiemetics 4

Postoperative Nausea and Vomiting

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

Critical Safety Considerations

Duration and Dose Limits

• Never exceed 5 days of treatment for any indication to minimize risk of tardive dyskinesia 1, 2
• Never exceed 30 mg daily in adults 1, 2
• The risk of tardive dyskinesia increases substantially with chronic use, particularly in elderly patients 2
• Even short-term, low-dose use (30 mg total over several days) has been associated with severe, long-lasting extrapyramidal symptoms lasting up to 13 months 5

Renal Impairment

• Reduce initial dose by 50% when creatinine clearance is below 40 mL/min 1, 3
• Titrate based on clinical response and tolerability 3

Hepatic Impairment

• Use with caution in severe hepatic impairment 1
• Metoclopramide undergoes minimal hepatic metabolism, so dose adjustment is generally not required unless renal function is also compromised 3

Administration Routes

Intravenous Administration

• Doses up to 10 mg: administer slowly over 1-2 minutes 3
• Doses exceeding 10 mg: dilute in 50 mL of normal saline and infuse over at least 15 minutes 3
• Compatible with normal saline for up to 48 hours when protected from light 3

Oral Administration

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

Intramuscular Administration

• 10 mg IM for postoperative nausea or when oral route is not feasible 3

Common Pitfalls and Contraindications

Absolute Contraindications

• Pheochromocytoma, seizure disorders, gastrointestinal bleeding, gastrointestinal obstruction 2
• Parkinson's disease or dementia with Lewy bodies (high risk of severe extrapyramidal symptoms) 2

Management of Extrapyramidal Reactions

• If acute dystonic reactions occur, administer 50 mg diphenhydramine IM immediately 3
• Symptoms typically resolve rapidly with diphenhydramine treatment 3
• Prophylactic diphenhydramine may be considered in younger patients receiving high-dose metoclopramide 6

Age-Related Considerations

• Patients over 59 years require careful monitoring and may need dose reduction due to higher risk of adverse effects 1
• Younger adults and children have increased susceptibility to extrapyramidal reactions, particularly at doses ≥2 mg/kg 6

Alternative Antiemetics When Metoclopramide is Contraindicated

• 5-HT3 receptor antagonists: Ondansetron 4-8 mg two to three times daily or granisetron 1 mg twice daily are highly effective first-line alternatives 2
• Dopamine antagonists: Prochlorperazine 5-10 mg four times daily or haloperidol 0.5-1 mg every 6-8 hours 2