Displaying 1 results of Eperisone Stable Isotopes Eperisone is a muscle relaxant medication that is used to relieve muscle spasms and stiffness. Stable isotopes of eperisone are non-radioactive forms of the drug that have been labeled with heavier isotopes of carbon, nitrogen, or oxygen. These isotopes are useful in drug metabolism studies that require tracing the fate of the drug molecule in the body.