What is the recommended oral dosing regimen for metoclopramide (Reglan) in children older than one month?

Metoclopramide (Reglan) Oral Dosing in Pediatric Patients

For children older than one month, metoclopramide should be dosed at 0.1 to 0.15 mg/kg per dose orally, administered every 6 to 8 hours, with a maximum of 0.5 mg/kg/day or 40 mg/day total, and treatment duration should not exceed 5 days due to significant risk of extrapyramidal symptoms. 1, 2

Standard Dosing Algorithm

Age-Based Dosing Restrictions

• Infants under 1 month: Metoclopramide is contraindicated due to immature hepatic and renal clearance, with elimination half-lives up to 23 hours compared to 4-6 hours in older children 2
• Infants 1-12 months: Use only when absolutely necessary at 0.1 mg/kg per dose every 8 hours (maximum 0.3 mg/kg/day), as this age group has significantly prolonged drug clearance 2, 3
• Children >1 year: Standard dosing of 0.1-0.15 mg/kg per dose every 6-8 hours can be used 1, 2

Weight-Based Calculation Examples

• 10 kg child: 1-1.5 mg per dose, 3-4 times daily (maximum 6 mg/day) 2
• 20 kg child: 2-3 mg per dose, 3-4 times daily (maximum 10 mg/day) 2
• 30 kg child: 3-4.5 mg per dose, 3-4 times daily (maximum 15 mg/day) 2
• ≥40 kg child: May use adult dosing of 10 mg per dose, 3-4 times daily (maximum 30-40 mg/day) 1

Critical Safety Considerations

Extrapyramidal Symptom Risk

• Incidence: Extrapyramidal symptoms occur in approximately 9% (95% CI 5-17%) of pediatric patients, with higher rates at doses ≥2 mg/kg 4, 5
• Age vulnerability: Younger children and adolescents have significantly higher risk than middle-aged adults 5, 6
• Dose relationship: Risk increases dramatically at doses ≥2 mg/kg, with 15% experiencing acute dystonic reactions and 33% developing akathisia 5
• Premature infants: Dystonic reactions can occur after just 2 doses due to prolonged plasma clearance 3

Maximum Duration Mandate

• Treatment should be limited to 5 days maximum to minimize risk of tardive dyskinesia and other neurological complications 1
• European regulatory agencies have mandated this 5-day limit across all indications due to safety concerns 1

Administration Timing and Route

Oral Administration

• Onset of action: 30-60 minutes after oral dosing 2
• Peak concentration: 1-2 hours after administration 2
• Duration of effect: 1-2 hours 2
• Timing for nausea/vomiting: Administer 30 minutes before meals and at bedtime for gastroparesis 1

Bioavailability

• Oral bioavailability is 80% ± 15.5%, making oral dosing nearly as effective as parenteral routes for most indications 2

Common Adverse Effects Beyond EPS

• Diarrhea: 6% (95% CI 4-9%) of patients 4
• Sedation: 6% (95% CI 3-12%) in multiple-dose studies 4
• Drowsiness and fatigue: Common, particularly in younger children 6

Contraindications and Precautions

Absolute Contraindications

• Infants under 1 month of age 2, 3
• Seizure disorders (metoclopramide lowers seizure threshold) 1
• Pheochromocytoma (risk of hypertensive crisis) 1
• Gastrointestinal obstruction or perforation 1

Relative Contraindications Requiring Dose Reduction

• Renal impairment: When creatinine clearance <40 mL/min, initiate at approximately one-half the recommended dose due to reduced drug clearance 1, 2
• Severe hepatic impairment: Use with extreme caution and consider dose reduction 1
• Premature infants: Avoid if possible; if essential, use lowest dose (0.1 mg/kg every 8-12 hours) with close monitoring 3

Clinical Context Considerations

Limited Efficacy Data

• Despite widespread use, there are insufficient reliable data to support efficacy of metoclopramide in pediatric gastroesophageal reflux or chemotherapy-induced nausea 2
• The FDA label explicitly states that efficacy has not been established in pediatric populations, though pharmacokinetics have been studied 2

Alternative Considerations

• For chemotherapy-induced nausea, ondansetron (0.15 mg/kg per dose, maximum 16 mg) has superior evidence and safety profile in children ≥6 months 7
• For gastroparesis, metoclopramide remains the only FDA-approved medication but should be used with heightened caution in pediatric patients 1

Monitoring Requirements

• Observe for extrapyramidal symptoms (dystonia, akathisia, parkinsonian symptoms) during each dose administration 5, 3
• If dystonic reactions occur, discontinue immediately and administer diphenhydramine 1-2 mg/kg IV/IM (maximum 50 mg) 8
• Reassess need for continued therapy daily, aiming to discontinue before 5-day maximum 1