CLAIMS 1. A method of enhancing the action of a pharmaceutical agent which is characterised in that it is a CPNS agent selected from the group of compounds acting on the central or peripheral nervous system, but excluding coal tar solution and H1-antagonist antihistamines and also excluding anti-inflammatory, analgesic and antipyretic agents, comprising the step of formulating the agent with an administration medium which is a solution of nitrous oxide gas in a pharmaceutical 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: 5w3], decosahexaenoic acid [C22: 6co3], ricinoleic acid and derivatives thereof selected from the group consisting of the Cl 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.

2. A pharmaceutical preparation characterised in that it comprises a pharmaceutical agent which is a CPNS agent selected from the group of compounds acting on the central or peripheral nervous system, but excluding coal tar solution and H1-antagonist antihistamines and also excluding anti-inflammatory, analgesic and antipyretic agents, comprising the step of formulating the agent 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: 5CI) 33 decosahexaenoic acid [C22: 6co3], ricinoleic acid and derivatives thereof selected from the group consisting of the Cl 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.

3. The method of claim 1 or the preparation of claim 2 wherein the essential fatty acid or ester thereof, component of the composition comprises a mixture of esters of the fatty acids listed above and is preferably constituted by the complex known as Vitamin F Ethyl Ester having a typical fatty acid distribution as follows : < C16 : 0 Cl6 o : 8,3 % Ci8o : 3,5 % Cis. i : 21,7 % Cis. 2: 34, 8 % Cis. 4 : 28,0 % > C18 : 1, 6 % unknown: 2, 1 %.

4. The method or the preparation of claim 3 wherein the administration medium further includes eicosapentaenoic acid [C20: 5w3] and/or decosahexaenoic acid [C22: 6w3] as additional long chain fatty acids.

5. The method of claim 1 or the preparation of claim 2 wherein the carrier solvent is water (preferably deionised water) or any of the pharmaceutical acceptable alcohols, ethers, polymers such as a polyethyleneglycol or the like or an oil which is preferably an organic oil which organic oil is further preferably an essential oil based on long chain fatty acids having between 14 and 22 carbon atoms in the fatty acid and is preferably of natural origin and most preferably a plant oil rich in gamma linolenic acid [GLA].

6. The method of claim 1 or the preparation of claim 2 wherein the CPNS agent is formulated in a liquid presentation and wherein the formulation incorporate, as part of the administration medium, water or acceptable other liquid solvent into which the nitrous oxide is dissolved, preferably to saturation, and wherein the fatty acid or ester thereof is dissolved or suspended or emulsified along with the CPNS agent.

7. The method of claim 1 or the preparation of claim 2 wherein the CPNS agent is formulated to be applied as a topical, buccal or vaginal cream or ointment or as a cutaneous patch, or as an intravenous, intramuscular or subcutaneous injection, or as a suppository, and wherein the formulation used in making up such cream, ointment, injectable formulation or suppository incorporates, along with the CPNS agent to be enhanced, a quantity of water containing, and preferably saturated with, nitrous oxide, the long chain fatty acid or ester thereof and the anti-infective agent formulated therewith, and, optionally further incorporates such additional excipients and carriers as are conventionally used in the pharmaceutical trade in making up such dosage forms.

8. A method of claim 1 or a composition of claim 2 wherein the CPNS agent is selected from the group consisting of the following classes of compounds: Central nervous system stimulants including central analeptics, psycho analeptics (antidepressants), respiratory stimulants, hallucinogenic medicines; Central nervous system depressants including anaesthetics, sedatives, hypnotics, barbiturates, non-barbiturates, anticonvulsants, (including anti-epileptics), tranquillisers (including phenothiazines and their derivatives, rauwolfia, diphenylmethane and its derivatives, alkyl diols and their derivatives), centrally acting muscle relaxants ; Local anaesthetics; and Medicines affecting autonomic functions including adrenomimetics (sympathomimetics), adrenolytics (sympatholytics), cholinomimetics (cholinergics), cholinolytics (anticholinergics) (including anti-Parkinsonism preparations), Ganglion blockers, anti-emetics and anti-vertigo preparations, decongestants,-hydroxytryptamine (serotonin) and serotonin antagonists, and anti-Alzheimers agents.

9. The method of claim 1 or the preparation of claim 2 wherein the active agent is selected from the group consisting of: A. the Central Nervous System Stimulants consisting of i. the following Central Analeptics : Amphetamine, Dextroamphetamine, Methamphetamine, Methylphenidate, Caffeine, Caffeine citrated, Caffeine and Sodium Benzoate, Clomipramine, Desipramine, Ephedrine, Imipramine, Pemoline, Protryptiline, ii. the following Psycho Analeptics (antidepressants): a. the Tricyclic Antidepressants being: Amitryptyline, Amoxapine, Clomipramine, Desipramine, Doxepin, Imipramine, Nortriptyline, Protriptyline, Trimipramine, b. the Monamine Oxidase Inhibitors being: Isocarboxazid, Phenelzine, Tranylcypromine, c. Other Antidepressants being: Burpopion, Fluoxetine, Fluvoxamine, Maprotiline, Mitrazapine, Moclobemide, Nefazodone, Paroxetine, Setraline, Trazodone, Venlafaxine, iii. The following Respiratory Stimulants (Bronchodilators) : Albuterol, Ephedrine, Ethylnorepinephrine, <BR> <BR> Fenoterol, Isoproterenol, Metaproteronol,<BR> <BR> <BR> <BR> <BR> <BR> Terbutaline, iv. The following Hallucinogenic medicines: a. the following Indoleamine hallucinogenics : LSD, DMT, N, N-dimethylamine, Psilocybin, b. the following Phenethylamines : Mescaline, Dimethoxymethylamphetamine (DOM), Methylenedioxyamphetamine (MDA), MDMA, B. the Central nervous system depressants consisting of: The following anaesthetics: Halothane, Isoflurane, Enflurane, Methoxyflurane, Sevoflurane, Desflurane, Methohexital, Thiopental, Etomidate, Ketamine, Propofol, ii The following Sedatives and Hypnotics: Alprazolam, Brotizolam, Chlordiazepoxide, Clobazam, Clonazepam, Clorazepate, Demoxepam, Diazepam, Estazolam, Flumazenil, Flurazepam, Halazepam, Lorazepam, Midazolam, Nitrazepam, Nordazepam, Oxazepam, Prazepam, Quazepam, Temazepam, Traizolam, iii the Barbiturates being: Amobarbital, Aprobarbital, Butabarbital, Butalbital, Mephobarbital, Methohexital, Pentobarbital, Phenobarbital, Secobarbital, Thiopental, iv the Non-barbiturates being: Buspirone, Chloral hydrate, Chlormezanone, Diphenhydramine, Doxylamine, Ethchlovynol, Ethinamate, Glutethemide, Hydroxyzine, Meprobamate, Methotrimeprazine, Methyprylon, Promethazine, Propiomazine, Propofol, Zolpidem, Zolpiclone, Paraldehyde, v. The Anticonvulsants, (including anti-epileptics) being: Acetazolamide, Amobarbital, Carbamazepine, Clobazam, Clonazepam, Clorazepate, Corticotropin, Diazepam, Divalproex, Ethosuximate, Ethotoin, Felbamate, Fosphytoin, Gabapentin, Lorazepam, Magnesium sulfate, Mephenytoin, Mephobarbital, Metharbital, Methsuximide, Nitrazepam, Paraldehyde, Paramethadione, Pentobarbital, Phenacemide, Phenobarbital, Phensuximide, Phenytoin, Primidone, Secobarbital, Trimethadione, Valproate sodium, Valproic acid, vi. The following Tranquillisers (including phenothiazines and their derivatives, rauwolfia, diphenylmethane and its derivatives, alkyl diols and their derivatives) being: a. Phenothiazines and derivatives being; Acetophenazine, Chlorpromazine, Chlorprothixene, Flupenthixol, Fluphenazine, Mesoridazine, Methotrimprazine, Pericyazine, Perphenazine, Pipotiazine, Prochlorperazine, Promazine, Thiopropazate, Thioproperazine, Thioridazine, Thiothixene, Trifluoperazine, Trifluoropromazine, b. Other Antipsychotics being: Clozapine, Fluspirilene, Haloperidol, Loxapine, Molindone, Olanzapine, Pimozide, Risperidone, Lithium, C Centrally acting muscle relaxants consisting of: Baclofen, Carisoprodol, Chlorphenesin, Chlorzoxazone, Cyclobenzaprine, Dantrolene, Diazepam, Lorazepam, Metaxalone, Methocarbamol, Orphenadrine, and Orphenadrine citrate, Phenytoin, D Local anaesthetics consisting of: Articaine, Benzocaine, Bupivacaine, Chloroprocaine, Cocaine, Diphenhydramine, Etidocaine, Lidocaine, Mepivacaine, Pramoxine, Prilocaine, Procaine, Propoxycaine, and Procaine, Proraracain, Ropivacaine, Tetracaine, E Medicines Affecting Autonomic Functions consisting of: i The Adrenomimetics (Sympathomimetics) consisting of: Phenylethylamine, Epinephrine, Norepinephrine, Dopamine, Dobutamine, Colterol, Ethylnorepinephrine, Isoproterenol, Isoetharine, Metaproterenol, Terbutaline, Metaraminol, Clonidine, Phenylephrine, Tyramine, Hydroxyamphetamine, Ritodrine, Prenalterol, Methoxamine, Albuterol, Amphetamine, Methamphetamine, Benzphetamine, Ephedrine, Phenylpropanolamine, Mephentermine, Phentermine, Fenfluramine, Propylhexedrine, Diethylpropion, Phenmetrazine, Phendimetrazine, ii The Adrenolytics (sympatholytics) consisting of: Phenoxybenzamine and related Haloalkylamines, Phentolamine, Prazosin, Terazosin, Doxazosin, Trimazosin, Indoramine, Labetalol, Ketanserin, Urapidil, Alfuzosin, Bunazosin, Tamsulosin, Yohimbine, Propanolol, Metoprolol, Nadolol, Atenolol, Timolol, Esmolol, Pindolol, Acebutolol, Labetalol, Bopindolol, Oxprenolol, Penbutolol, Carvedilol, Medroxalol, Bucindolol, Levubunolol (Betagan) glaucoma, Metipranolol, Bisoprolol, Nebivolol, Betaxolol (Betoptic) Glaucoma, iii The Cholinomimetics (cholinergics) consisting of: Acetylcholine, Metacholine, Carbachol, Betanechol, Pilocarpine, Muscarine, Arecoline, Oxotremorine, Ambenonium, Domperidone, Edrophonium, Edrophonium & Atropine, Metoclopramide, Neostigmine, Physostigmine, Pyridostigmine, iv The Cholinolytics (anticholinergics) (including anti-Parkinsonism preparations) consisting of: Amantadine, Anisotropine, Atropine, Scopolamine and related Belladonna alkaloids, Ipratropium bromide, Benztropine, Biperidine, Chlorpromazine, Clidinium, Dicyclomine, Diphenhydramine, Ethopropazine, Glycopyrollate, Homatropine, Hyoscyamine, Mepenzolate, Methantheline, Methoctramine, Hexahydrosiladifenidol, Himbacine, Tripitamine, Methscopolamine, Orphenadrine HCI, Pirenzepine, Procyclidine, Propantheline, Scopolamine, Thioridazine, Trihexyphenidyl, Carbidopa and Levodopa, Levodopa, Pergolide, Selegiline, v Ganglion blockers consisting of: Hexamethonium, Trimethaphan, Mecamylamine, vi Histamine and antihistaminic agents consisting of: 2 (m-F-phenylhistamine), Dimaprit, R-a-Me-histamine, Ethanolamines as Carbinoxamine maleat, Clemastinefumurate, Diphenhydramine HCI, Dimenhydrinate, Ethylenediamines as Pyrilamine maleat, Tripelennamine HCI, Tripelennamine citrate, Alkylamines as Chlorpheniramine maleat, Brompheniramine maleat, Piperazines as Hydroxyzine HCI, Hydroxyzine pamoate, Cyclizine HCI, Cyclizine lactate, Meclizine HCI, Phenotiazines as Promethazine HCI, Second generation Alkylamines as Acrivastine, Second generation Piperazines as Cetrizine HCI, Piperidines as Astemizole, Levocabastine HCI, Loratadine, Terfenadine, vii. Anti-emetics and Antivertigo preparations consisting of: 5-HT3 Antagonists as Ondansetron, Granisetron, Tropisetron, Dolasetron, D2/5-HT3 Antagonist as Metoclopramide, Trimethobezamide, D2 Antagonists as Phenotiazines namely Chlorpromazine, Perphenazine, Prochlorperazine, Promethazine, Thiethylperazine, Triflupromazine, D2 Antagonists as Benzimidazole derivatives namely Domperidone, D2 Antagonists as Butyrophenones namely Haloperidol, Droperidol, Corticosteroids as Dexamethasone, Methylprednisolone, Cannabinoids as Dronabinol, Nabilone, Hl antagonists Diphenhydramine, Meclizine, Cyclizine, Antimuscarinic agents as Scopolamine, Benztropiane, Benzodiazepines as Lorazepam, Alprazolam, Hl Antagonist as Dimenhydrinate, viii. Decongestants consisting of : Oxymetazoline, Phenylephrine, Xylometazoline ix.-hydroxytryptamine (serotonin) and serotonin antagonists consisting of a. 5-HT Agonists being: Buspirone, ipsaperone, Sumatriptan, Cisapride, b. 5-HT Antagonists being: Methysergide, Risperidone, Ketanserin, Ondansetron, c. 5-HT transport inhibitors being: Fluoxetine, Sentraline, and F Anti-Alzheimers agents consisting of: Physostigmine, Tacrine and Lecithin in combination with Tacrine.