Reversible Acetylcholinesterase Inhibitors

Reversible acetylcholinesterase inhibiting drugs reversibly bind to acetylcholinesterase (AChE) resulting in increased acetylcholine in the synaptic space.  Drugs in this class are used in the diagnosis and treatment of myasthenia gravis.

Myasthenia Gravis is a chronic autoimmune neuromuscular disorder characterized by weakness in the voluntary muscles. It occurs when the body's immune system produces antibodies that block or destroy the acetylcholine receptors at the neuromuscular junction, which are necessary for communication between nerves and muscles. This disruption impairs muscle contraction, leading to symptoms such as muscle weakness, fatigue, and difficulty with activities like speaking, swallowing, and breathing. The severity of symptoms can fluctuate, and they often improve with rest.

Edrophonium has been used to diagnose myasthenia gravis. Administration in patients with suspected myasthenia will result in rapid improvement of symptoms. Neostigmine, and pyridostigmine have been used in the treatment of myasthenia gravis.

Pyridostigmine is used as an antidote for anticholinergic toxidromes.

Class Drugs

• Edrophonium

• Physostigmine

• Neostigmine

• Pyridostigmine

Class Mechanism of Action

• Reversibly inhibits acetylcholinesterase

Class Adverse Effects

• Diarrhea

• Urination

• Miosis

• Bradycardia

• Emesis

• Lacrimation

• Lethargy

• Salivation

Drug Table

Drug Name	Application	Comments	Image
Edrophonium	Diagnosis of myasthenia gravis; Patients with myasthenia will have rapid increase in strength when administered this drug; Assessment of cholinesterase inhibitory therapy by differentiating cholinergic or myasthenic crisis when administered	Short acting; (15-10 minutes)	"Mr Ed" and "Phone"
Physostigmine	Reverse anticholinergic drugs	Adverse Effects:; -Seizures (when administered in high doses or too quickly) ; -Bradycardia; -Hypotension	"Physiology Book" and "Mean Stick"
Neostigmine	Antidote for neuromuscular blockers; Management of symptoms of myasthenia gravis	Stimulates GI/Bladder	"Neo" and "Mean Stick"
Pyridostigmine	Management of myasthenia gravis	Intermediate acting (3-6 hours)	"Pyramid" and "Mean Stick"