- Drugs and herbal supplements that are known to be potent or moderate inhibitors or inducers of cytochrome P450 (CYP)3A are specifically excluded. Foods that are known to be potent or moderate inhibitors of CYP3A (for example, grapefruit, grapefruit juice, Seville oranges, or Seville orange juice) are also specifically excluded during the study. In addition, starfruit and starfruit juice are excluded during the PK phase of the study.