Green’s Dictionary of Slang

cola n.

[abbr. brandname Coca-Cola, thus play on its abbr. Coke/coke n.1 (1)]

(US drugs) cocaine.

[US] in Spears Sl. and Jargon of Drugs and Drink (1986).
D. Vrij ‘Tying Off’ on Inter-zone.org [Internet] Adding cola to the mix, adds a dimension of space. Its a rush drug, pure and simple, any time any where, a speedball junkie can find a place for a coke hit.