CARISOPRODOL ELIMINATION IN HUMANS

The elimination of the muscle relaxant drug, carisoprodol, was examine d in 10 healthy volunteers after an oral dose of 700 mg. In nine subje cts, carisoprodol was rapidly eliminated, with a mean half-life of 99 +/- 46 min, and extensively converted to meprobamate. Within 2.5 h aft er carisoprodol intake, meprobamate serum concentrations exceeded thos e of carisoprodol. Serum levels of meprobamate recorded (15-25 mumol/L ) indicate that meprobamate might contribute to the effect(s) of caris oprodol. One subject eliminated carisoprodol with an overall half-life of 376 min, and only small amounts of meprobamate were recorded. This subject was found to be a poor metabolizer of mephenytoin. In spiked human sera, protein binding of carisoprodol was in the range of 41-67% , whereas meprobamate was bound to a lesser extent, 14-24%.