I don't allow most drugs on my sets-- there are a couple performers who "have" to smoke weed before a scene, and if it doesn't impair their performance, I don't mind. I don't allow it before photos though, since it looks obvious in pictures. But even this is truly rare and I can think of maybe one time this year that it happened. There is absolutely no coke or anything like that allowed-- but honestly nobody ever brings it, so it's an issue I've never had to address. As far as whether or not the guys want to take Levitra, Viagra, etc-- that's entirely up to them and I don't mess with that.