Flexeril is a muscle relaxer. The time that Flexeril stays in one's system depends on the dosage of th drug taken, usually it is about 12 to 24 hours, on an average about 18 hours.
Flexeril stays in your system 1-3 weeks. The length of time it takes a drug to be eliminated from the body can be estimated as 5-7 times a drug's half-life.
