While 4<unk> s are approved in the US for the treatment of Alzheimer's Disease, only three of these are available commercially. The three available are rivastigmine, donepezil, and galantamine, while tacrine is not. They are generally used to treat Alzheimer's disease and dementia. If a benefit occurs, it is generally during the second or third month after starting. It is difficult to determine which<unk>  has greater efficacy, due to design flaws in head-to-head comparison studies. Pyridostigmine is used in the treatment of myasthenia gravis.
Cholinesterase inhibitor
Acetylcholinesterase inhibitor
GABA analogue
Heterocyclic antidepressant
Adenosine reuptake inhibitor
Atypical antidepressant
Glycine reuptake inhibitor
Tricyclic antidepressant