Physicochemical compatibility and stability of ketamine co-administered with selected supportive care drugs and parenteral nutrition in pediatric oncology.

PURPOSE: Ketamine has been previously administered as an anesthetic but recently gained importance as an analgesic in pediatric oncology. Despite its efficacy, continuous intravenous administration to children with cancer is interrupted when other essential drugs require infusion. This occurs because its compatibility with many drugs and lipid emulsions is unknown, causing inadequate pain management and patient discomfort. This study has assessed the physicochemical compatibility and stability of ketamine with selected drugs, based on usage frequency data, and lipid emulsion formulations administered to pediatric cancer patients at tertiary hospitals.

METHODS

Physicochemical compatibility of ketamine involved admixture with selected concentrations of drugs, for physical incompatibility. Admixtures of ketamine with lipid emulsions and the other drugs included determining ketamine's chemical concentration using high performance liquid chromatography (HPLC). Particle size analysis investigated lipid stability.

RESULTS

The HPLC assay was linear over a range of concentrations (0.05 mg/mL - 0.5 mg/mL), validated under forced degradation conditions causing no interferences and an intra- and inter-day precision less than 2%. Ketamine was highly stable with all drugs and lipid emulsions tested, retaining >90% of its concentration for all systems investigated for two hours. No additional physical incompatibility occurred., but amoxicillin incompatibility was confirmed. Lipid emulsion stability was maintained, with no system exceeding particle size limits.

CONCLUSIONS

Ketamine is safe to co-administer with AmBisome®, cyclizine, hydromorphone, Intralipid®, magnesium sulfate, metoclopramide, micafungin, potassium dihydrogen phosphate, sodium dihydrogen phosphate and vancomycin. Our findings are significant for improving pain management in vulnerable patients simultaneously administered the tested drugs with ketamine.