Increased clearance & potential breakthrough bleeding &/or contraceptive failure w/ enzyme inducers eg, anticonvulsants [eg, barbiturates (including phenobarb), primidone, phenytoin, carbamazepine, oxcarbazepine, topiramate], antibiotics/antifungals (eg, griseofulvin, rifampicin), St. John's wort, antiretroviral agents (eg, ritonavir, nelfinavir, nevirapine). Increased plasma conc w/ strong & moderate CYP3A4 inhibitors eg, azole antifungals (eg, itraconazole, voriconazole, fluconazole) & macrolides (eg, erythromycin); etoricoxib. May increase plasma & tissue conc of cyclosporin, tizanidine, theophylline. May decrease plasma conc & tissue conc of lamotrigine. May increase risk of ALT elevations w/ medicinal products containing ombitasvir/paritaprevir/ritonavir, dasabuvir w/ or w/o ribavirin, glecaprevir/pibrentasvir & sofosbuvir/velpatasvir/voxilaprevir. May influence results of certain lab tests eg, biochemical parameters of liver, thyroid, adrenal & renal function, plasma levels of carrier proteins (eg, corticosteroid-binding globulin & lipid/lipoprotein fractions), parameters of carbohydrate metabolism, coagulation & fibrinolysis.