Decreased plasma conc by nafcillin, carbamazepine, St, Johns's wort, phenobarb, phenytoin, rifabutin, rifampicin, thioridazine, modafinil, efavirenz, bosentan, ritonavir, lopinavir, etravirine, nevirapine. Decreased plasma conc of warfarin, dabigatran, voriconazole, PPIs. Increased plasma conc of amiodarone, quinidine, glyburide, statins, HMG-CoA reductase inhibitors, cyclosporine, sirolimus, tacrolimus, CYP2C8 & CYP3A substrates. Reduced plasma conc of other OC steroids. Increased/decreased plasma conc of repaglinide.