IT IS A REVERSIBLE CHOLINESTERASE INHIBITOR.WHILE THE PRECISE MECHANISM OF RIVASTIGMINE'S ACTION IS UNKNOWN, IT IS POSTULATED TO EXERT ITS THERAPEUTIC EFFECT BY ENHANCING CHOLINERGIC FUNCTION. THIS IS ACCOMPLISHED BY INCREASING THE CONCENTRATION OF ACETYLCHOLINE THROUGH REVERSIBLE INHIBITION OF ITS HYDROLYSIS BY CHOLINESTERASE.