I do agree that drug obtaining should be modified slightly, but a bit more complicated than your idea describes.
On one end are the drugs' effects quite strong so we try to keep the amount within the server balanced as much as we can, but on the other end, it is Vice City.
The complexity created to get yourself hard-drugs like heroin and cocaine is good, but I do feel like there should some more ways to do it.
I think there should be a couple more drugs added. For example Morphine, Vicodin or even common medications like Ibuprofen or Tylenol.
These are "drugs" supplied by dispensaries, and the extreme ones would only be obtainable through prescription.
Each drug would have a minor or major side effect, depending on the drug, and would also heal the using player.
Would be cool to connect this with EMS, since illegally acquired medications could result in serious charges when it comes to fraud and illegal possession.