Recommended Diluent for Remifentanil
Remifentanil should be reconstituted with Sterile Water for Injection, USP at a concentration of 1 mg per 1 mL, then further diluted with compatible IV fluids to final concentrations of 20,25,50, or 250 mcg/mL before administration. 1
Reconstitution Protocol
- Add 1 mL of diluent per mg of remifentanil and shake well to dissolve, yielding approximately 1 mg/mL 1
- Remifentanil must not be administered without dilution 1
Compatible IV Fluids for Dilution
The FDA label specifies that remifentanil is stable for 24 hours at room temperature after reconstitution and dilution with the following solutions 1:
- Sterile Water for Injection, USP
- 5% Dextrose Injection, USP
- 5% Dextrose and 0.9% Sodium Chloride Injection, USP
- 0.9% Sodium Chloride Injection, USP
- 0.45% Sodium Chloride Injection, USP
- Lactated Ringer's and 5% Dextrose Injection, USP
Important Stability Exception
- Lactated Ringer's Injection, USP (without dextrose) provides only 4 hours of stability at room temperature, not 24 hours 1
Recommended Final Concentrations
The concentration chosen depends on clinical context 1:
- 20 or 25 mcg/mL: Recommended for pediatric patients ≥1 year and for monitored anesthesia care 1
- 50 mcg/mL: Suitable for most adult applications 1
- 250 mcg/mL: Reserved for higher infusion rates in adults 1
Critical Incompatibilities
Do not administer remifentanil through the same IV tubing as blood products, as nonspecific esterases in blood will hydrolyze remifentanil to its inactive carboxylic acid metabolite 1
pH Considerations and Mixing Warnings
Research demonstrates that pH critically affects remifentanil stability when mixed with other agents 2:
- Isolated remifentanil at pH <4 remains stable for 24 hours 2
- Mixing with propofol (pH 7.35) substantially increases pH to 6.50 and causes significant remifentanil degradation 2
- Remifentanil reconstituted with sodium bicarbonate (pH 8.65) degrades significantly 2
Do Not Mix in Same Syringe
Remifentanil and propofol should never be mixed in the same syringe for TIVA, as they are immiscible—remifentanil solution separates from propofol emulsion and rises to the top, resulting in unpredictable and unreliable drug concentrations 3
Stability and Storage
- Reconstituted and diluted solutions are stable for 24 hours at room temperature (except with plain Lactated Ringer's) 1
- No antimicrobial preservative is present—strict aseptic technique is mandatory 1
- Solutions should be clear, colorless, and free of particulate matter before administration 1
Co-administration Compatibility
Remifentanil has been shown compatible with propofol (Diprivan®) when co-administered into a running IV administration set (not mixed in the same syringe) 1