No, really. Does Lex Luthor get high? Ride the powder? Kiss the sky? Take a long ride with Lucy is the Sky with Diamonds? Smoke Smoke?
Obviously, I'm talking about post-Crisis Luthor, the powerful businessman, not the pre-crisis Mad Scientist. That guy was clearly on something. I mean, look at him!
That's a man that indulges his appetites. Though we never really see him put away a large deep dish pizza, we do see him smoke and drink fine wine and aged scotch. He openly lusts after women and usually gets them. And legality never seems like an issue to Lex.
So why wouldn't he? Or rather, why do I have trouble actually imagining him doing drugs? I certainly don't see him rolling a joint. And maybe the Michael Rosenbaum young, hip Luthor might pop a tab of E before hitting a rave, but it's hard to imagine Superman's most deadly nemesis tripping out like that. Heroin seems a little... scruffy for the bald baddie. I guess I could imagine Lex snorting cocaine. It seems like a rich man's drug.
But I guess I can't imagine Luthor getting addicted to anything. Despite the amount of alcohol he seems to have in his desk, I never read a story with him drunk. He lights his cigars only when he wants to look non-chalant. And though he has pursued many women, he has always had a goal in mind beyond sex (which makes Lex one of the few male villains who use his sexuality as a weapon).
Drugs would be a thing he craves other than power. And since Lex trades on the desires of others, giving himself such a weakness seems... out of character.
So, while I can imagine The Penguin inhaling a line with that impressive nostril, The Cheetah being blissed out on H, or the Flash's Rogues passing around a fat doobie while reminiscing about the good old days, I have to think that Lex Luthor would just say "no."
(I think the Joker would say "no" too, not because he'd get addicted, but because there really isn't a drug out there that would make him more crazed)