The invention relates to novel compounds of formula (I): H2N-CH(R1)-CH2-S-S- CH2-CH(R2)-CONH-R5, wherein R1 is a hydrocarbon chain, phenyl or benzyl radical, methylene radical substituted by a 5 or 6 atom heterocycle; R2 is a phenyl or benzyl radical, a 5 or 6 atom aromatic heterocycle, methylene group substituted by a 5 or 6 atom heterocycle; R5 is a CH(R3)-COOR4 radical, wherein R3 is hydrogen, an OH or OR group, a saturated hydrocarbon group, a phenyl or benzyl radical and OR4 is hydrophile ester, or 5 or 6 membered heterocycle comprising several heteroatoms selected from a group consisting of nitrogen, sulphur and oxygen, with at least two nitrogene atoms, wherein said heterocycle is substitutable by an alkyl C1-C6, phenyl or benzyl radical. The use of the inventive compounds in the form of drugs, a pharmaceutical composition comprising said compounds, a pharmaceutically acceptable excipient, the use in conjunction of at least one type of cannabinoid derivative for potentiating the analgesic and antidepressant effect of the novel compounds of formula (I) and/or morphine or the derivatives thereof are also disclosed.