Rivastigmine improves the function of nerve cells in the brain. It works by preventing the breakdown of a chemical called acetylcholine (ah see til KO leen). People with dementia usually have lower levels of this chemical, which is important for the processes of memory, thinking, and reasoning. Rivastigmine is used to treat mild to moderate dementia caused by Alzheimer's or Parkinson's disease. Rivastigmine may also be used for other purposes not listed in this medication guide.