Dantrolene inhibition of the hepatic mixed function oxidase system

The effect of dantrolene sodium, a skeletal muscle relaxant, on the hepatic MFO system has been investigated. The dantrolene produces a dose related inhibition of the system. Single doses of 100 mg/kg and accumulative doses up to 125 mg/kg prolong pentobarbital sleeping time and decrease the rate of aminopyrine N-demethylation without altering cytochrome P450 content. However, single doses of 400 mg/kg and accumulative doses of 500 mg/kg do cause a decrease in cytochrome P450 content as part of the dantrolene induced inhibition of the hepatic MFO system.