4. Subjects taking the following sensitive cytochrome P450 (CYP) substrate medications that have a narrow therapeutic range are excluded from the study unless they can be transferred to other medications within ≥5 half-lives prior to dosing: paclitaxel (CYP2C8) warfarin, phenytoin (CYP2C9), S-mephenytoin (CYP2C19), thioridazine (CYP2D6), theophylline and tizanidine (CYP1A2).