What is the recommended dose of Ranitidine (Zantac) for children?

Ranitidine Dosing in Children

The recommended dose of ranitidine for children aged 1 month to 16 years is 5-10 mg/kg/day divided into 2-3 doses for GERD or peptic ulcer disease, with a maximum of 300 mg/day, according to FDA labeling and American Academy of Pediatrics guidelines. 1, 2

Standard Oral Dosing by Indication

Treatment of Duodenal and Gastric Ulcers

• 2-4 mg/kg twice daily (maximum 300 mg/day) for active ulcer treatment 2
• Maintenance dosing: 2-4 mg/kg once daily (maximum 150 mg/day) 2

GERD and Erosive Esophagitis

• 5-10 mg/kg/day divided into 2 doses for GERD treatment 1, 2
• For erosive esophagitis specifically, the higher end of this range (closer to 10 mg/kg/day) is typically needed 1

Intravenous Dosing for Critically Ill Children

For stress ulcer prophylaxis in pediatric intensive care patients, a minimum of 3 mg/kg/day IV is required, with doses titrated to maintain gastric pH ≥4. 3

• The commonly cited 2-4 mg/kg/day range results in poor gastric pH control in 36% of critically ill children 3
• Optimal IV dosing: 1.5 mg/kg every 6 hours (6 mg/kg/day total) achieves pH ≥4 in 80% of critically ill children 4
• Doses below 3 mg/kg/day result in poor control in 71% of patients versus only 19% with ≥3 mg/kg/day 3

Critical Pitfall in ICU Dosing

The standard pediatric reference dosing of 2-4 mg/kg/day is inadequate for critically ill children due to altered pharmacokinetics in this population. 3 Always start with at least 3 mg/kg/day and titrate upward based on gastric pH monitoring. 3

Age-Specific Considerations

Neonates and Preterm Infants

• **Preterm infants (<37 weeks): 0.5 mg/kg twice daily** to maintain gastric pH >4 5
• Term neonates: 1.5 mg/kg three times daily 5
• Preterm infants require significantly smaller doses due to prolonged drug effect and delayed time to peak pH 5
• Insufficient data exists for neonates <1 month of age to make definitive dosing recommendations 2

Children 4-11 Years

• A single 75 mg dose (the over-the-counter strength) effectively controls intragastric acidity for 5-6 hours in this age group 6
• This translates to approximately 2-3 mg/kg per dose for average-weight children in this age range 6

Intramuscular Dosing for Anaphylaxis

For anaphylaxis management, ranitidine IM dose is 1 mg/kg (maximum 50 mg) as second-line therapy combined with diphenhydramine. 7, 1, 8

• This is never administered as monotherapy—epinephrine remains first-line treatment 8
• The combination of diphenhydramine plus ranitidine is superior to diphenhydramine alone 7, 8
• For IV administration in anaphylaxis, dilute in 20 mL D5W and administer over 5 minutes 7, 8

Renal Impairment Adjustments

For creatinine clearance <50 mL/min, reduce dosing to 150 mg every 24 hours in adolescents, with proportional reductions for younger children. 2

• Hemodialysis removes ranitidine; time doses to coincide with the end of dialysis sessions 2
• Monitor closely and adjust frequency cautiously based on clinical response 2

Formulation and Administration

• Effervescent tablets (25 mg dissolved in 5 mL water) are preferred over peppermint syrup by 71% of children aged 4-8 years 9
• Better taste acceptance with effervescent formulation may improve compliance 9
• Available as 15 mg/mL syrup or 25 mg effervescent tablets 1, 9

Important Limitations

• Tachyphylaxis develops within 6 weeks of continuous use 1
• Ranitidine is less effective than PPIs for healing erosive esophagitis 1
• Requires 2-3 times daily dosing due to only 6-hour duration of acid suppression 1
• Note: Ranitidine was withdrawn from the US market in 2020 due to NDMA contamination concerns, though dosing guidelines remain relevant for understanding H2-blocker pharmacology in children