Ondansetron (Zofran) Compatibility with Lactated Ringer's Solution
Yes, ondansetron (Zofran) is physically and chemically compatible with lactated Ringer's solution for intravenous administration. 1, 2
FDA-Approved Compatibility
The FDA drug label for ondansetron injection explicitly states that ondansetron is compatible and stable at room temperature under normal lighting conditions for 48 hours after dilution with lactated Ringer's solution, along with other standard IV fluids including 0.9% sodium chloride and 5% dextrose. 1
Supporting Research Evidence
Stability Studies
Ondansetron maintains greater than or equal to 90% of its initial concentration when mixed with lactated Ringer's solution at concentrations of 24 and 96 micrograms/mL under multiple storage conditions, including up to 14 days refrigerated followed by 2 days at room temperature. 2
A comprehensive Y-site compatibility study testing 94 injectable drugs found ondansetron to be physically compatible with lactated Ringer's injection for 4 hours during simulated Y-site administration, with no visual incompatibility or particle formation detected. 3
Practical Administration Guidelines
For chemotherapy-induced nausea and vomiting:
- Dilute ondansetron injection in 50 mL of lactated Ringer's solution (or other compatible fluids) before administration to adult and pediatric patients. 1
- The diluted solution should be infused intravenously over 15 minutes. 1
- After dilution, do not use beyond 24 hours, although the solution remains chemically stable for 48 hours. 1
For postoperative nausea and vomiting:
- Dilution is not required before administration. 1
Important Preparation Considerations
Storage and Handling
- Inspect the diluted ondansetron solution for particulate matter and discoloration before administration; discard if present. 1
- Occasionally, ondansetron precipitates at the stopper/vial interface in vials stored upright, but potency and safety are not affected—resolubilize by shaking the vial vigorously. 1
- Although ondansetron is chemically stable when diluted as recommended, sterile precautions should be observed because diluents generally do not contain preservatives. 1
Incompatible Mixtures to Avoid
- Do not mix ondansetron with alkaline solutions, as a precipitate may form. 1
- Do not mix with solutions for which physical and chemical compatibility has not been established. 1
Clinical Context: When Lactated Ringer's May Be Contraindicated
While ondansetron is compatible with lactated Ringer's solution from a pharmaceutical standpoint, avoid using lactated Ringer's solution in patients with severe traumatic brain injury or head trauma (Glasgow Coma Scale <8) due to its slightly hypotonic nature (osmolarity 273-277 mOsm/L), which can worsen cerebral edema. 4, 5 In these patients, use 0.9% normal saline as the carrier fluid for ondansetron instead. 4