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.

Pyridostigmine is a reversible acetylcholinesterase inhibitor commonly used to manage myasthenia gravis. It enhances neuromuscular transmission by increasing acetylcholine availability at the neuromuscular junction, which helps improve muscle strength and function. Pyridostigmine is often preferred for its longer duration of action compared to other agents like neostigmine. Additionally, it has applications in treating certain cases of urinary retention and as a protective agent against nerve gas exposure.

Neostigmine is a reversible acetylcholinesterase inhibitor used primarily in the treatment of myasthenia gravis and to reverse the effects of neuromuscular blocking agents after surgery. Unlike physostigmine, neostigmine does not cross the blood-brain barrier, making it more suited for peripheral applications. It increases acetylcholine levels at neuromuscular junctions, enhancing muscle contraction and improving strength in affected patients. Neostigmine is also used in the management of urinary retention and to stimulate gastrointestinal motility.

Physostigmine is a reversible inhibitor of the enzyme acetylcholinesterase, which increases the levels of acetylcholine at synapses. It is primarily used to treat anticholinergic toxicity, particularly from drugs like atropine or scopolamine. Additionally, it can be used in the management of myasthenia gravis. Due to its ability to cross the blood-brain barrier, physostigmine can also address central nervous system effects of anticholinergic overdose. Its effectiveness and rapid action make it a critical agent in emergency medicine.

Pilocarpine is a natural alkaloid derived from the leaves of the jaborandi plant. It primarily acts as a muscarinic agonist, stimulating the secretion of saliva and sweat. Clinically, pilocarpine is used to treat dry mouth (xerostomia) in conditions like Sjögren's syndrome and as an eye drop to lower intraocular pressure in glaucoma. Its ability to enhance exocrine gland activity makes it a valuable therapeutic agent in managing these conditions.