Last June 11, TSA found the drugs (including an ounce of marijuana) in his check-on luggage.
Promethazine, an ingredient often found in cough syrup, is a sedative that contains codeine. When mixed with soda or other sweet beverages, it's called purple drank or sizzurp.
Two days earlier, 2 Chainz was reportedly robbed at gunpoint outside The Green Door dispensary at 843 Howard St. in San Francisco. The assailants took his wallet and cell phone. He later tweeted: "We definitely got geeked up in San Fran, best smoke in the world."