Nitro-oxyderivative compounds or salts thereof having the following general formula (I): A-(B).sub.b0-(C).sub.c0--NO.sub.2 wherein: c0 is an integer and is 0 or 1, b0 is an integer and is 0 or 1, A=R-T.sub.1-, wherein R is the radical of an analgesic drug for the chronic pain, in particular for the neuropathic pain; B is such that its precursor is selected from aminoacids, hydroxyacids, polyalcohols, compounds containing at least one acid function; C is a bivalent radical containing an aliphatic, heterocyclic or aromatic radical.