Green’s Dictionary of Slang

(drugs) opium.

1929		C.G. Givens ‘Chatter of Guns’ in Sat. Eve. Post 13 Apr.; list extracted in AS VI:2 (1930) 133: ope, n. Opium.
1959		J.E. Schmidt Narcotics Lingo and Lore.
2001		ONDCP Street Terms 16: Ope — Opium.
2005		R. Cea No Lights, No Sirens 154: Cho [...] suddenly became melancholy [...] maybe he realized how fucked he was. Then another wave of ‘ope’ rocked him and he was smiling again.