I think a little bit more of randomness when taking "enhancers" would be very interesting.  It may even solve market issues with coke.

I.E.

• "Quality" factor of drugs depending on how it was made, maybe not enough production ingredients used, maybe they are fake.  Would be interesting to make them look the same but maybe the description would just change alittle "questionable quality".
• Production for Coke could have a "wait period". And the longer you wait the better the quality.
  
• If you choose to wait the longest period to have say the highest quality which could still very even at the highest quality, then you would receive less product count.  Maybe Even 1.  And this is OK because markets naturally solve this issue.
• Lower quality Coke and higher quality for both share the 6-hour cooldown, however higher quality Coke gives you more.
  
• Low quality looks the same but lower amount of energy given only known once used only distinguishable by the smallest descriptive words.
  
• It would allow certain people to scam lower levels who don't know better or be forced to provide high quality to others that would smash them if they didnt.  Real life you know? 
  
• Maybe add drinking both alcohol and doing drugs at the same time affects each other in a bad way like in real life?
• Possibly add "speed" drug that enhances cocaine taking somehow.
  

This would in turn allow a flexible market and prices would naturally vary even if there were over saturation in a good way.  I also and others I think love the realistic drama that comes about in game due to game mechanics. People hating others because of themn selling bad quality drugs on purpose you know?