What is the recommended dose of ranitidine (Histamine H2-receptor antagonist) for adults?

Recommended Ranitidine Dosage for Adults

The standard recommended oral dosage of ranitidine for adults is 150 mg twice daily or 300 mg once daily at bedtime. 1

Dosing Guidelines by Indication

Gastrointestinal Conditions

• Duodenal Ulcer:

  • 150 mg twice daily OR
  • 300 mg once daily after evening meal or at bedtime 1
  • Maintenance therapy: 150 mg at bedtime 1

• Gastric Ulcer:

  • 150 mg twice daily 1
  • Maintenance therapy: 150 mg at bedtime 1

• GERD (Gastroesophageal Reflux Disease):

  • 150 mg twice daily 1

• Erosive Esophagitis:

  • 150 mg four times daily 1
  • Maintenance therapy: 150 mg twice daily 1

• Pathological Hypersecretory Conditions (e.g., Zollinger-Ellison syndrome):

  • Starting dose: 150 mg twice daily 1
  • May increase frequency as needed based on clinical response
  • Dosages up to 6 g/day have been used in severe cases 1

Special Populations

• Elderly (≥65 years):

  • No dosage adjustment required based on age alone 1

• Renal Impairment:

  • For creatinine clearance <50 mL/min: 150 mg every 24 hours 1
  • May increase to every 12 hours if clinically necessary, with caution
  • For hemodialysis patients: Schedule dose to coincide with end of hemodialysis 1

Administration Considerations

• Ranitidine can be taken with or without food
• For once-daily dosing, taking the medication at bedtime is often recommended to maximize acid suppression during nighttime hours 1
• For patients with acute hypersensitivity reactions, intravenous ranitidine can be administered at 50 mg for adults (diluted in 5% dextrose to 20 mL and injected over 5 minutes) 2

Efficacy and Safety Profile

• Ranitidine is 4-10 times more potent than cimetidine in inhibiting stimulated gastric acid secretion 3
• The safety profile is excellent with adverse events reported in only 20% of patients (compared to 27% with placebo) in clinical trials 4
• No evidence of dose-related toxicity has been observed across an eightfold range of therapeutic doses 4

Important Considerations

• Doubling the dose from 150 mg twice daily to 300 mg twice daily has not shown significant improvement in symptom relief for patients with persistent GERD symptoms 5
• For most indications, 150 mg twice daily is as effective as higher doses, with the convenience of once-daily dosing (300 mg) being an option for improved compliance 1, 6

Remember that ranitidine is a histamine H2-receptor antagonist that works by inhibiting gastric acid secretion and is effective for conditions where reducing stomach acid is beneficial.