Enzyme induction following surgery with halothane and neurolept anesthesia.

Salivary antipyrine clearance was determined before and 4 or 8 days after surgery as a measure of enzyme induction in 25 patients given halothane anesthesia and in 29 patients given neurolept anesthesia for uncomplicated otic surgical procedures. Statistically significant but clinically small increases in antipyrine clearance of 20% and 16% were measured in the halothane and neurolept groups, respectively. Similar decreases in antipyrine half-life were observed; apparent volume of distribution was unchanged. These changes are interpreted as representing a clinically insignificant degree of enzyme induction in most patients. The cause of these changes is not readily apparent. They may be due to the administration of anesthetic and adjuvant drugs, to the stress associated with the entire surgical experience, or to a combination of these factors.