The invention provided a method of enhancing the action of a pharmaceutical agent selected from the group consisting of the CPNS agents selected from the group of compounds acting on the central or peripheral nervous system, and for a formulation of such agents characterised in that the agent is formulated with an administration medium which is characterised in that it comprises a solution of nitrous oxide gas in a pharmaceutically acceptable carrier solvent for the gas and which administration medium includes at least one fatty acid or ester or other suitable derivative thereof selected from the group consisting of oleic acid, linoleic acid, alpha-linolenic acid, gamma-linolenic acid, arachidonic acid, eicosapentaenoic acid [C20: 5 omega 3], decosahexaenoic acid [C22: 6 omega 3], ricinoleic acid and derivatives thereof selected from the group consisting of the C1 to C6 alkyl esters thereof, the glycerol-polyethylene glycol esters thereof and the reaction product of hydrogenated natural oils composed largely of ricinoleic acid based oils such as castor oil with ethylene oxide.
