What is the typical dosage and usage of Ranitidine (Zantac) for treating conditions like gastroesophageal reflux disease (GERD), peptic ulcers, and Zollinger-Ellison syndrome in adults and pediatric patients?

Ranitidine Dosing and Usage

Ranitidine is no longer available in most markets due to FDA withdrawal in 2020, but when it was used, standard dosing for adults was 150 mg twice daily for GERD and peptic ulcers, with pediatric dosing at 2-4 mg/kg twice daily (maximum 300 mg/day) for ulcers and 5-10 mg/kg/day divided in 2-3 doses for GERD. 1

Adult Dosing by Indication

Duodenal Ulcer (Active)

• Standard regimen: 150 mg twice daily 1
• Alternative regimen: 300 mg once daily after evening meal or at bedtime for patients requiring dosing convenience 1
• Healing rates: 90-100% of ulcers heal after 2 months of treatment 2

Gastric Ulcer (Benign)

• Treatment: 150 mg twice daily 1
• Maintenance: 150 mg at bedtime after healing 1

GERD (Gastroesophageal Reflux Disease)

• Standard dose: 150 mg twice daily 1
• Important caveat: Ranitidine was less effective than proton pump inhibitors for GERD, with PPIs demonstrating superior healing rates and symptom control 3

Erosive Esophagitis

• Treatment: 150 mg four times daily 1, 4
• Maintenance: 150 mg twice daily after healing 1
• Comparative efficacy: Ranitidine 150 mg QID produced healing rates of 49%, 67%, and 77% at 4,8, and 12 weeks respectively, which was superior to cimetidine 800 mg BID 4

Zollinger-Ellison Syndrome

• Initial dose: 150 mg twice daily 1
• Dose adjustment: May require more frequent 150 mg dosing based on individual needs 1
• Maximum reported: Up to 6 g/day in patients with severe disease 1
• Duration: Continue as long as clinically indicated 1

Maintenance Therapy

• Duodenal ulcer: 150 mg at bedtime reduces recurrence to approximately 30% during first 12 months 1, 2
• Gastric ulcer: 150 mg at bedtime reduces recurrence to approximately 20% during first 12 months 2

Pediatric Dosing (Ages 1 Month to 16 Years)

Duodenal and Gastric Ulcers

• Treatment: 2-4 mg/kg twice daily, maximum 300 mg/day 1
• Maintenance: 2-4 mg/kg once daily, maximum 150 mg/day 1

GERD and Erosive Esophagitis

• Dosing: 5-10 mg/kg/day divided in 2-3 doses 5, 1
• Duration of action: Approximately 6 hours, necessitating 2-3 times daily administration 5
• Formulations: Available as peppermint-flavored syrup and effervescent tablets for easier pediatric administration 5

Important Pediatric Limitations

• Insufficient data for neonates less than 1 month of age 1
• Tachyphylaxis: Diminishing response develops within 6 weeks of treatment initiation, limiting long-term use 5
• Comparative efficacy: PPIs (particularly omeprazole 0.7-3.3 mg/kg/day) are more effective than ranitidine for symptom relief and healing erosive esophagitis in children 5

Special Populations

Renal Impairment

• Creatinine clearance <50 mL/min: 150 mg every 24 hours 1
• Dose escalation: May increase to every 12 hours if clinically required, with caution 1
• Hemodialysis: Time scheduled dose to coincide with end of hemodialysis session, as dialysis reduces circulating ranitidine levels 1

Elderly Patients

• Monitoring: Exercise caution in dose selection due to higher likelihood of decreased renal function 1
• Recommendation: Monitor renal function and adjust dosing accordingly 1

Clinical Context and Current Status

Historical Role

• Ranitidine was 7 times more potent than cimetidine with longer duration of action 3
• Demonstrated efficacy in reducing water-electrolyte losses in short bowel syndrome when administered intravenously 3
• Continuous infusion at lower dosage was more efficient than intermittent infusion 3

Limitations Compared to PPIs

• Acid suppression: Traditional H2RA doses do not prevent most NSAID-related gastric ulcers 3
• GERD treatment: PPIs proven superior to ranitidine for preventing NSAID ulcer recurrence and overall symptom control 3
• Erosive esophagitis: Standard PPI doses (omeprazole 20 mg, lansoprazole 30 mg daily) more effective than ranitidine for healing 6

Current Treatment Paradigm

• First-line therapy: PPIs are now recommended as initial treatment for GERD, with single-dose PPI taken 30-60 minutes before meals 7
• Pediatric preference: Omeprazole is the preferred agent for children with GERD due to superior efficacy and FDA approval down to age 2 years 7, 5
• H2RA role: When H2RAs are used currently, they serve as adjunctive therapy for breakthrough nocturnal symptoms, though limited by tachyphylaxis 3

Important Clinical Caveats

• Withdrawal from market: Ranitidine was withdrawn by the FDA in 2020 due to NDMA contamination concerns, making this information primarily of historical relevance [@General Medical Knowledge]
• Refractory cases: For patients with idiopathic gastric acid hypersecretion and refractory ulcers, doses up to 1800 mg/day ranitidine were used safely for periods longer than 6 months [@9@]
• Combination with aspirin: Limited data exist on ranitidine's protective effects against low-dose aspirin-related gastric injury [@1