Tacrine hydrochloride is an acetylcholinesterase inhibitor that was one of the first medications approved for the treatment of Alzheimer's disease. By increasing levels of acetylcholine in the brain, tacrine aims to enhance cognitive function and slow the progression of symptoms associated with dementia. Although it can improve cognitive abilities in some patients, its use has diminished due to side effects, such as gastrointestinal issues and hepatotoxicity, as well as the availability of newer, more effective treatments.

Edrophonium chloride is a short-acting reversible acetylcholinesterase inhibitor primarily used for diagnostic purposes in myasthenia gravis. It helps to temporarily increase acetylcholine levels at the neuromuscular junction, leading to improved muscle strength. The edrophonium test can quickly determine whether a patient has myasthenia gravis or if their symptoms are due to other causes. Due to its rapid onset and short duration of action, edrophonium is also used in acute situations to reverse the effects of neuromuscular blockers during surgery.