Only rarely, though, barbiturates, carbamazepine, Efavirenz, nevirapine, oxcarbazepine,
rifampin, and rifamycin, which are also CYP3A4 inducers, can decrease the plasma concentrations of atorvastatin.
Efavirenz should be taken when your stomach is empty,
which means taking it one hour before a meal, or waiting until two hours after you have eaten.