Mutagenicity studies with volatile metabolites of halothane.

The mutagenicities of two volatile metabolites of halothane, 2-chloro-1,1,1-trifluoroethane (CF3CH2Cl) and 2-chloro-1,1-difluoro-ethylene (CF2CHCl), and a presumed halothane metabolite, 2-bromo-2-chloro-1,1-difluoroethylene (CF2CBrCl), were investigated in the bacterial assay system developed by Ames and co-workers. Both gas-phase and liquid culture tests were made. In addition, mutagenicity of CF2CBrCl was studied in a modified Ames test system using rapidly growing cells in enriched liquid medium. The purity of tested compounds was verified by combined gas chromatography and mass spectrometry. In the standard Ames test, CF3CH2Cl and CF2CBrCl were not mutagenic, and CF2CHCl was only weakly mutagenic. CF2CBrCl was detectable as weakly mutagenic, however, in the modified Ames test using rapidly growing cells. Although these results are reassuring, the effects of long-term exposure to halogenated anesthetics are still not fully known.