Compounds of formula I are effective in treating disorders modulated by opiate receptor activity and/or monoamine activity. 1 In formula I, R1 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl; R2 is selected from hydrogen, hydroxy, cyano, haloalkyl, glycosyl, SO2R5, and OR5; R3 and R4 are independently selected from hydrogen and lower alkyl, or R3 and R4 taken together with nitrogen form a five- or six-membered heterocyclic or substituted heterocyclic ring; and R5 is selected from alkyl, aryl, alkylaryl, substituted alkyl, substituted aryl, and substituted alkylaryl.