Green’s Dictionary of Slang

(US drugs) prescription cough syrup, containing codeine; thus as v.

1996		UGK ‘3 in the Mornin’’ 🎵 ’Cause I’m leanin’ off the dank and the good ole drink.
2004		T.I. ‘24’s’ 🎵 I’ve been dranking and I've been smoking / Flying down 285 but I'm focused.
2007		UGK ‘Quit Hatin’ The South’ 🎵 I’m bumped the school, that’s how I do, sippin drank, each teen night.
2008		N.Y. Times 11 Feb. 🌐 Prescription cough syrup — sometimes diluted, and often called ‘drank’ or ‘lean’ or ‘purp’ — is the recreational drug most closely associated with Houston’s fertile hip-hop scene.
2008		The Ampersand 6 Feb. 🌐 It’s about purple stuff/syrup/purple drank/lean, a popular recreational drug concoction which combines cough syrup and (usually) Sprite.
2009		J. Stahl Pain Killers 119: What are you, a Houston rapper? [...] Hitting the purple drank now?
2015		Guardian Rev. 13 Nov. 4/3: His ever-increasing appeite for ‘lean’ or ‘purple drank’. A mixture of prescription cough syrup containing promethazine and codeine.