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 anminoacids, hydroxyacids, polyalcohols, compounds containing at least one acid function; C is a bivalent radical containing an aliphatic, heterocyclic or aromatic radical.