the acetylcholinesterase inhibitors according to the invention as above defined do not present the undesired side effects as miosis and block of accomodation reflex with resultant focusing problems in near vision , changes in the function of all the secretory glands , including lacrimal , bronchial , sweat , salivary , antral , intestinal , and acinar pancreatic glands , nausea , vomit , gastric acid hyper - secretion , abdominal pains , diarrhoea , fainting or pre - fainting sensation , disturbances of cardio - vascular functions . the administration is well tolerated by patients and allows to obtain the desired results even with a single oral administration daily . the present invention obviously refers to pharmaceutical compositions containing as active principle an acetylcholinesterase inhibitor having central activity possibly in combination with the usual excipient used for preparing pharmaceutical composition for oral administration for the treatment of the above said pathologies . in particular the compositions according to the invention will contain the active principle in quantities comprised between 1 . 5 - 12 mg , more preferably 5 - 10 mg . the symptomatic , acute treatment is normally performed by administering orally to the patient a single dosage containing from 0 . 1 to 50 mg daily , preferably 0 . 5 to 40 mg daily , more preferably 1 to 30 mg daily of active principle ; while for the chronic treatment the same administration can be repeated once a day for 40 - 80 days . among the compounds useful according to the present invention particularly preferable are : donepezil or a pharmacologically acceptable salt thereof , rivastigmine or a pharmacologically acceptable salt thereof and metrifonate . in the present invention , the term “ pharmacologically acceptable salt thereof ” include the salts of inorganic acids , such as hydrochloride , hydrobromide , sulfate , nitrate and phosphate , and those of organic acids , such as formate , acetate , oxalate , succinate , maleate , fumarate , methanesulfonate , benzenesulfonate and toluenesulfonate . among these , hydrochloride is more preferable . in practising the present invention , the acetylcholinesterase inhibitor compounds of the present invention may be orally or parentally administered . in general , the are administered in the form of tablet , granule , capsule and syrup , and in the form of injection , such as intravenous , subcutaneous and intramuscular injection , suppositories or sublingual tablets . the dose will vary depending upon the symptom , age , sex , body weight , sensitivity of patients , method of administration , time and interval of administration and property , dispensing , and kind of pharmaceutical preparations , kind of effective ingredients , etc . pharmaceutical preparations in the form of , e . g ., tablet , granule , capsule , syrup , injections are prepared according to the usual manner . various groups of patients suffering from different kind of migraine were treated with 5 mg of donepezil hydrochloride daily . the results are reported in the following histograms 1 to 6 ( see fig1 - 6 ). fig1 — shows the number of hours with pain before and after 60 days chronic treatment with donepezil hydrochloride ( 5 mg / die ) measured in tests on 17 patients suffering from chronic migraine , otherwise known as “ transformed migraine ” ( international headache society criteria ). fig2 — shows the number of migraine attacks before and after chronic donepezil hydrochloride treatment ( 5 mg / die ) for the above said group of patients . fig3 — shows the number of hours with pain before and after chronic treatment with donepezil hydrochloride ( 5 mg / die ) measured in tests on 18 patients suffering from migraine without aura . fig4 — shows the number of migraine attacks before and after donepezil hydrochloride treatment ( 5 mg / die ) for the same group of patients as in fig3 . fig5 — shows the results of prophylaxis of migraine with donepezil hydrochloride reporting the number of migraine attacks following 60 days run - in and 60 days treatment in 35 patients suffering from severe migraine without aura . fig6 — shows the results of prophylaxis of migraine with donepezil hydrochloride reporting the hour with pain following 60 days run - in and 60 days treatment for the same group of patients as in fig5 . moreover , 8 patients suffering from migraine attacks longer than 72 h were treated with 20 mg of donepezil hydrochloride acutely given , also in this case the results were highly satisfactory . systemic pain of muscles , tendons , viscera ( oesophagus , stomach , colon ); these syndromes are considered particularly difficult to hale . tests performed on 16 patents ( same conditions as those described for the migraine tests ) showed an improvement of the patient &# 39 ; s conditions in 60 % of the cases treated and total disappearance of the pain in 10 % of the cases . in the pain syndromes caused by denervation or amputation pain develops on the limb or body part which is denervated and therefore is insensible to nociceptive stimuli (“ painful anaesthesia ”). nine patients who had no advantages after treatment with antiinflammatory analgesica or opioids were tested in the same conditions as above described . all patients showed an high tolerance to the treatment , with side effects much lower then those observed in the case of administration of the commonly available acute and prophylactic therapies for curing migraine and central neurogenic pain .
methods of use of donepezil having central action for the treatment of function and / or organic central pain syndromes are disclosed .