Trouble with the ILLEGAL drugs was that he never knew what it REALLY was.
When it was REALLY only shoe polish - that's was just a drag.
But once when the supply dried up there was only that black goo the dealer said was hash oil. But it got him layed out flat like opium for a week - That week when he only ever got up to get stoked again.
Ironically it's lucky he didn't know that it was probably REALLY junk. For the end of that week he'd have been asking for H if he'd known. And lived that dramatic tragic life - and been REALLY dead years ago.
With the legal drug the doctor prescibes now at least he knows some of what that drug REALLY is.