i'm guessing you want more, but FA (2003) lists a few. That's likely to be all I can remember...
Increase P450 activity - barbiturates, phenytoin, carbamazepine, rifampin, griseofulvin, quinidine
Decrease P450 activity - cimetidine, ketoconazole, grapefruit, erythromycin, isoniazid, sulfonamides