The present invention relates to nitrooxyderivatives or salts thereof having the following general formula (I): R--NR.sub.1c--(K).sub.k0--(B).sub.b0--(C).sub.c0--NO.sub.2 (I) whereinc0, b0 and k0 are 0 or 1;R is the radical of an analgesic drug for chronic pain, for instance neurophatic pain;R.sub.1c is H or alkyl with from 1 to 5 carbon atoms;B is such that its precursor is selected from amino acids, hydroxy acids, polyalcohol, compounds;C is a bivalent radical containing an aliphatic, heterocyclic or aromatic radical.