The invention relates to a product comprising (1R)-1-[(({2R)-2-amino-3-[(8S)-8-(cyclohexylmethyl) -2-phenyl-5,6-dihydroimidazo [1,2-a]pyrazin-7(8H)-yl]-3-oxopropyl}dithio)methyl]-2-[(8S)-8-(cyclohexylmethyl) -2-phenyl-5,6-dihydrolmidazo[1,2-a]pyrazin-7(8H)-yl]-2-oxoethylamine in association with an analgesic agent selected from morphine, the similar or a morphine derivative, sodium channel inhibitors, non-steroidal antiflammatory agents (AINS), glutamatergic system inhibitors, tricycle antidepressants and gabaergic derivatives for simultaneous therapeutic use which is separated or out over the time for pain treatment or prevention.