Disclosed herein are methods of using metaxalone. In one embodiment, the method comprises determining that a patient in need metaxalone therapy is taking a substance that is a n inhibitor or an inducer of a cytochrome p450 isozyme, wherein the cytochrome P450 is CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, or CYP3A4, and adjusting administration to the patient of metaxalone or the substance to avoid an adverse event associated with metaxalone. In another embodiment, the method comprises informing a user that metaxalone is metabolized by a cytochrome p450 isozyme, wherein the cytochrome P450 is CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, or CYP3A4. 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.