Ranitidine Dosing for Adults and Pediatric Patients
Adult Dosing
For gastro-oesophageal reflux disease (GERD) in adults, ranitidine 150 mg twice daily orally is the recommended dose, while peptic ulcer disease can be treated with either 150 mg twice daily or 300 mg once daily at bedtime. 1
Oral Dosing by Indication
- GERD: 150 mg twice daily is the standard regimen 1
- Erosive esophagitis: 150 mg four times daily for acute treatment, then 150 mg twice daily for maintenance 1
- Duodenal ulcer: 150 mg twice daily or 300 mg once daily at bedtime (both equally effective) 1, 2, 3
- Gastric ulcer: 150 mg twice daily for acute treatment 1, 4
- Maintenance therapy: 150 mg at bedtime for both duodenal and gastric ulcers 1
The 300 mg bedtime dosing is particularly effective because overnight gastric acidity plays a critical role in ulcer pathogenesis 2. For severe erosive esophagitis, higher doses (300 mg four times daily) achieve significantly better healing rates (75% at 8 weeks) compared to standard dosing (54% at 8 weeks) 5.
Intravenous Dosing
- Standard IV dose: 50 mg per dose for adults 6
- Anaphylaxis management: 50 mg IM (1 mg/kg, maximum 50 mg) as second-line therapy combined with diphenhydramine 7, 6
- IV administration technique: Dilute in 20 mL D5W and administer over 5 minutes 7, 6
Pediatric Dosing (Ages 1 Month to 16 Years)
For pediatric GERD and peptic ulcer disease, the American Academy of Pediatrics recommends 5-10 mg/kg/day divided into 2-3 doses, with a maximum of 300 mg/day. 7
Oral Dosing by Indication
- GERD and erosive esophagitis: 5-10 mg/kg/day divided into 2 doses (maximum 300 mg/day) 7, 1
- Duodenal and gastric ulcers (acute): 2-4 mg/kg twice daily (maximum 300 mg/day) 1
- Maintenance therapy: 2-4 mg/kg once daily (maximum 150 mg/day) 1
Intramuscular Dosing for Anaphylaxis
- Pediatric IM dose: 1 mg/kg per dose (maximum 50 mg), used as second-line therapy with diphenhydramine 7, 6
- The combination of diphenhydramine plus ranitidine is superior to diphenhydramine alone 7
Important caveat: There is insufficient data for neonates less than 1 month of age, and dosing recommendations cannot be made for this population 1.
Renal Impairment Adjustments
For patients with creatinine clearance <50 mL/min, reduce the dose to 150 mg every 24 hours. 1
- If clinically necessary, frequency may be cautiously increased to every 12 hours 1
- Hemodialysis removes ranitidine; ideally time the dose to coincide with the end of dialysis 1
- Elderly patients require careful dose selection due to age-related decline in renal function 1
Clinical Limitations and Alternative Medications
Ranitidine develops tachyphylaxis within 6 weeks of continuous use and requires 2-3 times daily dosing due to its 6-hour acid suppression duration. 7
When to Consider Alternatives
- Proton pump inhibitors (PPIs) are superior to H2-antagonists for healing erosive esophagitis 8, 7
- PPIs (omeprazole 20-40 mg twice daily before meals for at least 8 weeks) should be considered first-line for GERD-related cough and severe reflux 8
- For refractory cases, combination therapy with twice-daily PPIs plus nocturnal H2-antagonists achieves full acid suppression 8
- Prokinetic agents (metoclopramide 10 mg three times daily) may be required in some patients with GERD 8
Important Safety Considerations
- Ranitidine is very well tolerated with infrequent serious adverse reactions 9
- Unlike cimetidine, ranitidine lacks antiandrogenic effects even at high doses 9
- Chronic antacid therapy is not recommended due to metabolic side effects and limited efficacy compared to H2-antagonists and PPIs 10
- In anaphylaxis, H2-antagonists are second-line therapy and should never be administered alone without epinephrine 6