CHEMICAL COMPATIBILITY OF REGIONAL ANESTHETIC DRUG-COMBINATIONS

OBJECTIVE: To define the physical and chemical compatibilities of several classes of drugs that may be used in combination for peridural anesthesia. DESIGN: Morphine, fentanyl, bupivacaine, lidocaine, ketamine, and clonidine were admixed for one hour in five of three-drug combinations, plus one group of all seven drugs. combinations were inspected macroscopically and microscopically to determine physical compatibility. The admixtures were evaluated by gas chromatography/mass spectroscopy (GC/MS) and compared with known standard to determine chemical compatibility. RESULTS: The admixtures showed no physical incompatibility on microscopic or macroscopic evaluation. Chemical compatibility of all mixtures was confirmed by GC/MS. Ion chromatograms of the drugs in admixtures were identical to previously established standards. CONCLUSIONS: The agents evaluated demonstrated physical and chemical compatibility under conditions that would be observed during the administration of peridural anesthesia. Combinations of these drugs therefore could be safely admixed for use in anesthesia.