On the other hand, co-prescribing of strong CYP3A4/5 inhibitors such as azole antifungals (e.g., itraconazole and voriconazole) and strong inducers of CYP3A4/5, such as rifampin and carbamazepine, with ETI, warrants careful consideration, as these combinations may not produce the desired therapeutic benefit for people with CF. This evidence concerns the gene CYP3A4 and cystic fibrosis.