Drugs are an important aspect in the GTA series. Drugs take place in every single Grand Theft Auto game, they are sold, bought (for others), and used by characters around the protagonist on many occasions.
Adrenaline in the GTA III era games were sometimes mentioned as drugs by GTA fans. There was also a deleted feature where in Grand Theft Auto: San Andreas, Carl Johnson would be able to smoke weed which would make the camera wobble around making hard to control CJ.
In Grand Theft Auto: Vice City, while driving the Cherry Popper Ice Cream Factory truck, Tommy Vercetti distributes drugs.
In Grand Theft Auto: Vice City Stories, the player make business empires for drug manufacturing and distribution.
In Grand Theft Auto: Chinatown Wars, the protagonist Huang Lee can control stocks of drugs and buy them and sell them to other drug dealers which is a good way to make money. There are six types of drugs the
player can deal: cocaine, heroin, downers, acid, marijuana, and ecstasy. On three occasions, Huang has to get drugs as 'buy ins' before initiating a mission.