Intravenous Ranitidine (Rantac) Dosing Protocol
For IV ranitidine administration, give 50 mg per dose for adults (or 1 mg/kg for pediatric patients, maximum 50 mg) diluted in 5% dextrose to a total volume of 20 mL and administered over 5 minutes. 1
Adult Dosing
- Standard IV dose: 50 mg per administration 1
- Dilute in 5% dextrose to 20 mL total volume 1
- Administer over 5 minutes to minimize adverse effects 1
- Can be repeated as needed based on clinical response 1
The evidence supports this as the standard approach for acute management, particularly in settings like anaphylaxis where ranitidine serves as second-line therapy alongside antihistamines. 1
Pediatric Dosing
- Dose: 1 mg/kg per administration 1, 2
- Maximum single dose: 50 mg (even in larger children) 1, 2
- Dosing range: 12.5-50 mg depending on weight 1
- Same dilution and administration protocol as adults 1
For chronic oral therapy in children with GERD or peptic ulcer disease, the American Academy of Pediatrics recommends 5-10 mg/kg/day divided into 2-3 doses (maximum 300 mg/day), but this differs from acute IV administration. 2
Clinical Context and Limitations
- Ranitidine is second-line therapy and should never be administered alone in anaphylaxis—epinephrine remains first-line 1
- Combination of diphenhydramine plus ranitidine is superior to diphenhydramine alone for anaphylaxis management 1
- Ranitidine develops tachyphylaxis within 6 weeks of continuous use 2
- Less effective than proton pump inhibitors for healing erosive esophagitis 2
Important Safety Note
Ranitidine (Zantac/Rantac) was withdrawn from markets worldwide in 2020 due to NDMA contamination concerns. While the dosing information above reflects historical guidelines, clinicians should verify current availability and regulatory status in their region before prescribing. Alternative H2-receptor antagonists (famotidine) or proton pump inhibitors should be considered as replacements.