Microbiological stability of a fentanyl, bupivacaine and clonidine mixture in a 0.9% sodium chloride infusion stored in syringes and reservoirs.

Combinations of extradural opioids and local anesthetic solutions are used in clinical practice, although little information exists on their microbiological or chemical stability. Currently there are no commercially available, prepacked, ready-to-use epidural mixtures of these medications and all mixtures must be prepared by the pharmacist. Epidural analgesic mixtures have been prepared on an as-needed basis. The aim of this study was to investigate the microbiological stability of a fentanyl, bupivacaine and clonidine mixture in a 0.9% sodium chloride infusion (without preservatives), prepared by the pharmacist in order to provide a basis for recommendations on the exchange of containgers (polypropylene syringes and polyvinylchloride [PVC] reservoirs). This mixture maintained microbiological stability for at least 28 days when prepared under aseptic conditions using a laminar air flow station, with a grade A environment and a B background, and using sterile clothes and equipment. During aseptic preparation in a grade A environment, less than 1 colony forming unit (CFU)/m3 and less than 3500 particles greater than 0.5 micrometers with no particle being greater than 5 micrometers, and in a grade B environment less than 10 CFU/m3 and less than 350,000 particles greater than 0.5 micrometers and less than 2,000 particles greater than 5 micrometers are allowed. Putatuive in situ antimicrobial activity of the drug mixture did not interfere with sterility testing. A pH difference was observed over time between the polypropylene syringes and the PVC reservoirs.