- Participants taking a drug known to be moderate and strong inhibitors or inducers of isoenzyme CYP3A (protoocol Appendix C). Participant must be off CYP3A inhibitors and inducers for at least two weeks prior to starting study drug. NOTE: participants must avoid consumption of Seville orange (and juice), grapefruit or grapefruit juice, grapefruit hybrids, pummelos and exotic citrus fruits from 7 days prior to the first dose of study drug and during the entire study treatment period due to potential CYP3A4 interaction.