Intramuscular Ranitidine Dosing Based on Weight
The recommended intramuscular (IM) dose of ranitidine is 1 mg/kg, which can be administered as needed for conditions such as anaphylaxis. 1
Adult Dosing
- Standard IM ranitidine dose for adults is 50 mg per dose 1
- Available in 25 mg/mL concentration for IM administration 2
- Typically administered as a single injection, with dosing adjusted based on clinical response 1
Pediatric Dosing
- For children, the recommended IM dose is 1 mg/kg per dose 1
- Dosing range of 12.5 to 50 mg (1 mg/kg) is appropriate for pediatric patients 1
- The maximum single dose should not exceed 50 mg, even in larger children 1
Administration Considerations
- Ranitidine injection is available in single-use vials containing 50 mg/2 mL (25 mg/mL) and multi-dose vials containing 150 mg/6 mL (25 mg/mL) 2
- For IM administration, the drug should be injected into a large muscle mass 2
- When used in anaphylaxis management, ranitidine can be diluted in 5% dextrose to a total volume of 20 mL and administered over 5 minutes (for IV route) 1
Special Populations
- In patients with renal impairment, dose adjustment may be necessary as ranitidine clearance correlates with glomerular filtration rate 3
- For neonates and infants, careful dosing is required due to their immature renal function 3
- Elderly patients may require dose reduction due to age-related changes in renal function 4
Clinical Pearls
- In anaphylaxis management, H2 antagonists like ranitidine are considered second-line therapy to epinephrine and should never be administered alone 1
- A combination of diphenhydramine and ranitidine is superior to diphenhydramine alone for managing anaphylaxis 1
- Ranitidine has an excellent safety profile across a wide dosage range 5
- The onset of action for IM ranitidine is typically within 15 minutes, with effects lasting 6-8 hours 6, 4
Monitoring
- Monitor for adverse effects including headache, dizziness, and rarely, cardiac arrhythmias 5
- In pediatric patients, monitor intragastric pH when possible to confirm adequate acid suppression 7
- For patients with renal impairment, monitor for signs of CNS toxicity including confusion, agitation, and hallucinations 4