Disclosed herein is a method of using metaxalone. In one embodiment, the method comprises obtaining metaxalone from a container providing information that metaxalone affects the activity of a cytochrome p450 isozyme. In another embodiment, the method comprises informing a user that metaxalone affects the activity of a cytochrome p450 isozyme. Also included are articles of manufacture comprising a container containing a dosage form of metaxalone, wherein the container is associated with published material informing that metaxalone affects activity of a cytochrome p450 isozyme. Also disclosed are a method of treatment and a method of manufacturing a metaxalone product.