- Treatment with strong inhibitors and/or inducers of cytochrome P450 2C19 (CYP2C19) and cytochrome P450 3A4 (CYP3A4). Consumption of CYP3A4 enzyme inducing or inhibiting herbal drugs, fruit juices and beverages (example, grapefruit, grapefruit juice, quinine [tonic water], star fruit, St John's Wort) within 2 weeks prior to start of trial medication until the end of Day 21