A sigma ligand for use in the treatment of opioid-induced hyperalgesia associated to opioid therapy, wherein the sigma ligand has the general formula: wherein R 1 is selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted non-aromatic heterocyclyl, substituted or unsubstituted aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, -COR 8, -C OR 8, - C NR 8 R 9, -CH=NR 8, -CN, -OR 8, -OC R 8, -S t -R 8, -NR 8 R 9, - NR 8 C R 9, -NO 2, -N=CR 8 R 9, and halogen; R 2 is selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, - COR 8, -C OR 8, -C NR 8 R 9, -CH=NR 8, -CN, -OR 8, -OC R 8, -S t -R 8, -NR 8 R 9, -NR 8 C Rg, -NO 2, -N=CR 8 R 9, and halogen; R 3 and R 4 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, -COR 8, -C OR 8, -C NR 8 R 9, -CH=NR 8, -CN, -OR B, -OC R 8, -S t -R 8, -NR 8 R 9, -NR 8 C Rg, -NO 2, -N=CR 8 R 9, and halogen, or together they form an optionally substituted fused ring system; R 5 and R 6 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, -COR 8, -C OR 8, -C NR 8 R 9, -CH=NR 8, -CN, -OR 8, -OC R 8, -S t -R 8, -NR 8 R 9, -NR 8 C Rg, -NO 2, -N=CR 8 R 9, and halogen, or together form, with the nitrogen atom to which they are attached, a substituted or unsubstituted, aromatic or non-aromatic heterocyclyl group; n is selected from 1, 2, 3, 4, 5, 6, 7 and 8; t is 1,2 or 3; R 8 and R 9 are each independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, and halogen; or a pharmaceutically acceptable salt, stereoisomer or solvate thereof. R 1 is selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted non-aromatic heterocyclyl, substituted or unsubstituted aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, -COR 8, -C OR 8, - C NR 8 R 9, -CH=NR 8, -CN, -OR 8, -OC R 8, -S t -R 8, -NR 8 R 9, - NR 8 C R 9, -NO 2, -N=CR 8 R 9, and halogen; R 2 is selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, - COR 8, -C OR 8, -C NR 8 R 9, -CH=NR 8, -CN, -OR 8, -OC R 8, -S t -R 8, -NR 8 R 9, -NR 8 C Rg, -NO 2, -N=CR 8 R 9, and halogen; R 3 and R 4 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, -COR 8, -C OR 8, -C NR 8 R 9, -CH=NR 8, -CN, -OR B, -OC R 8, -S t -R 8, -NR 8 R 9, -NR 8 C Rg, -NO 2, -N=CR 8 R 9, and halogen, or together they form an optionally substituted fused ring system; R 5 and R 6 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted arylalkyl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted heterocyclylalkyl, -COR 8, -C OR 8, -C NR 8 R 9, -CH=NR 8, -CN, -OR 8, -OC R 8, -S t -R 8, -NR 8 R 9, -NR 8 C Rg, -NO 2, -N=CR 8 R 9, and halogen, or together form, with the nitrogen atom to which they are attached, a substituted or unsubstituted, aromatic or non-aromatic heterocyclyl group; n is selected from 1, 2, 3, 4, 5, 6, 7 and 8; t is 1,2 or 3; R 8 and R 9 are each independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, substituted or unsubstituted, aromatic or non-aromatic heterocyclyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryloxy, and halogen;