Inappropriate for whom? I'm not sure how brief, tasteful nudity or drug references automatically make a show "inappropriate". It truly depends on the person for whom you are considering the show.
As a blanket statement, however, it has more than drug references -- there is blatant drug use. (mostly pot) addtionally, there are MANY sexual references/situations.
Personally: I would suggest High School and up, but I'm sure there are individuals younger that could handle it. My kids 12 & 8 listen to the recording constantly and I don't censor it in any way. But bring them to see it? Not yet.
If we're not having fun, then why are we doing it?
These are DISCUSSION boards, not mutual admiration boards. Discussion only occurs when we are willing to hear what others are thinking, regardless of whether it is alignment to our own thoughts.