whenever you are trying to figure the elimination time of a drug....
1. look up its half-life this is the amount of time that it takes for half of the drug to be eliminated. wikipedia.org is good for this purpose, so too is rxlist.com. Find the drug you are curious about and then look under its pharmacokinetic's which is where you'll find the info you want.
2. then mulitiply the half life number of hours by 5
According to rxlist: Carisoprodol is eliminated by both renal and non-renal routes with a terminal elimination half-life of approximately 2 hours. The half-life of meprobamate is approximately 10 hours.
Meaning that the metabolite of soma ---> meprombate has a total elimination time of 50 hours or about 2 days. Always remeber that half-life is an approximation! If you need to pass a drug test I would give myself a solid week or not fool around at all. But other users are correct that soma/meprombate is not tested for on a standard drug test.
True drug test are not tested for muscle relaxers BUT they do have a benzo metabolite. Therefore, taking for a long term or daily can show up in benzo catagory. Know people this has happened to. And if taken daily after stopping could take 30 dys to get out of system.
Drug test are usually not performed for Soma. it is not a narcotic substance