PREPARATION OF PH-ADJUSTED LOCAL-ANESTHETICS

Characteristics of alkalinized local anesthetics are poorly described with regard to stability and precipitation. Current fixed-volume metho ds of alkalinization often result in unstable, precipitated solutions of unpredictable pH. We determined a stable, nonprecipitating, anesthe tic mixture and used it in a randomized double-blind crossover study o f 21 patients to evaluate alkalinized anesthetic solutions in reducing pain on injection. Our solution significantly reduced pain associated with retrobulbar injection (analysis of variance, P=.0362) but not th at associated with Nadbath injection. Fixed-volume alkalinization is n ot recommended because complications can result with the use of precip itated anesthetics.