Injectable Ranitidine (Rantac) Dosing and Administration
The standard intramuscular (IM) dose of ranitidine is 50 mg every 6 to 8 hours for adults, with no dilution necessary. 1
Adult Dosing
- For adults, the recommended IM dose is 50 mg per dose, administered every 6 to 8 hours 1
- For intravenous (IV) administration, ranitidine can be given as:
- Intermittent bolus: 50 mg every 6 to 8 hours, diluted to a concentration no greater than 2.5 mg/mL and injected at a rate no greater than 4 mL/min 1
- Intermittent infusion: 50 mg every 6 to 8 hours, diluted to a concentration no greater than 0.5 mg/mL and infused over 15-20 minutes 1
- Continuous IV infusion: 6.25 mg/hour (150 mg in 250 mL of compatible solution at 10.7 mL/hour) 1
Pediatric Dosing
- For children, the recommended total daily dose is 2 to 4 mg/kg, divided and administered every 6 to 8 hours 1
- The maximum single dose should not exceed 50 mg, even in larger children 2
- For specific conditions like anaphylaxis management, the pediatric IM dose is 1 mg/kg per dose, with a dosing range of 12.5 to 50 mg 2
Special Populations
- For patients with impaired renal function (creatinine clearance <50 mL/min), the recommended dose is 50 mg every 18 to 24 hours 1
- If clinically necessary, the frequency may be increased to every 12 hours with caution 1
- For hemodialysis patients, dosing should ideally be scheduled to coincide with the end of hemodialysis 1
- Elderly patients may require dose adjustments due to decreased renal function 1
Administration Technique
- For IM injections, administer in the gluteal region, specifically in the posterior lateral aspect of the upper buttocks to avoid major nerves and blood vessels 3
- Use the upper outer quadrant of the buttock to avoid sciatic nerve injury 3
Higher Dose Requirements
- In some patients with pathological hypersecretory conditions (like Zollinger-Ellison syndrome), higher doses may be necessary 1
- For Zollinger-Ellison patients, continuous IV infusion can be started at 1.0 mg/kg/hour and adjusted upward in 0.5 mg/kg/hour increments based on gastric acid output measurements 1
- Dosages up to 2.5 mg/kg/hour and infusion rates as high as 220 mg/hour have been used in these cases 1
Efficacy Considerations
- Studies have shown that continuous IV infusion tends to maintain more consistent intragastric pH control compared to bolus injections 4, 5
- Continuous infusion of ranitidine maintained pH above 4 for 52% of the time compared to 40% with repeated boluses in one study 5