Whether for a combat edge, to treat psychological or physical wounds, drugs are there to even take that edge off stressful life in New Carthage.
Legal medicine can be bought from pharmacies. As for the good stuff, dealers might no be dealing on every corner, but there are drug runners you can get in contact with, and if that fails - certain places in the city may offer some of the illegal substances, hassle-free from a vending machine.
There are more than one way to administer narcotics - through epidermal application, syringe injection or when the heat is on and you're in the middle of a fight - through some cybernetics designed to do just that.
In the climate of New Carthage, unless properly stored drugs won't last too long once out of the bag, so be smart!