There are conflicting answers on the web. My guess is that it would not show up in most standard drug tests; it is a muscle relaxer not an opiate and is not a controlled substance. We don't answer questions about drug clearance from a person's system because we don't want to enable addictive behavior or non-physician use of drugs.
You should be fine with any drug test so long as you bring your doctor's prescription to the test. Good luck!