Abstract

Feeding of sulfanilamide, sulfapyridine, sulfathiazole, sulfadiazine, or N⁴-acetylsulfanilamide to mice for two and one-half days causes them to be anesthetized by smaller amounts of pentobarbital than are normal mice. The final mean blood levels of the five sulfonamides were respectively, 6,8,5,15, and 7 mgm. per cent (total).

Sulfanilamide reduces the median lethal dose of pentobarbital by about the same absolute amount as the median anesthetic dose.

Sulfanilamide also reduces the concentration of ether and chloroform necessary to anesthetize mice.

Twenty-four hours after the withdrawal of sulfanilamide, the effect on the reaction to ether has at least in part disappeared.

One-half hour after the intravenous injection of sulfanilamide, there is much less effect on the anesthetic dose of pentobarbital than after two and one-half days of feeding of sulfanilamide.