A method for treating the symptoms of multiple sclerosis and related neurodegenerative conditions, using a histamine compound that is methylated in vitro prior to being introduced into the body of the patient. The histamine compound is suitably histamine diphosphate, and may be methylated in vitro by mixing in combination with at least one thiol compound in the presence of at least one methyl group donor compound. The thiol compound is suitably L-reduced glutathione and the methyl group donor is suitably betaine hydrochloride. The compounds are mixed vigorous in an acid environment, to create a shearing force that facilitates exchange of the methyl group from the donor compound to the histamine diphosphate. The resulting methylated histamine compound is suitably administered to the patient by transdermal application. The method also provides a medicament for treatment the symptoms of multiple sclerosis and related neurodegenerative conditions, and a method for preparation of such a medicament.
