re: Where in the enumerated powers are federal drug laws?

I’ll concur with this to some degree. There is a certain fiscal reality with federalism. The Food Drug and Cosmetic Act was driven because people were dying from patent medicines. The federal treasury gives them the ability to police the bad actors. StTe treasuries don’t do this.

Now if we move to reduce federal tax assessments and/or move to more block rather than categorical grants, then you can efficiently police at a state level. Until then, there is some necessity on geceral enforcements