Anticholinesterase Inhibitors in Pharmacology

Indirect-Acting (Anticholinestrase)

• Inhibit acetylcholinesterase enzyme, increasing acetylcholine (ACh) levels

Reversible Anticholinesterase (AChE Inhibitors)

• Bind to the active center of acetylcholinesterase (AChE) enzyme, inactivating it through conformational change
• Indirectly stimulate both nicotinic and muscarinic acetylcholine receptors

Edrophonium (Enlon®, Enlon-Plus®)

• A short-acting AChE inhibitor
• Quaternary amine, so actions are limited to the periphery (does not pass the blood-brain barrier)
• Rapidly absorbed and has a short duration of action due to rapid renal elimination

Pharmacokinetics

• Onset of action: IV (30-60 seconds), IM (2-10 minutes)
• Duration of action: IV (5-10 minutes), IM (5-30 minutes)
• Half-life: 7-12 minutes
• Elimination time: 33-110 minutes

Uses

• Diagnosis of myasthenia gravis: IV injection of edrophonium leads to rapid increase in muscle strength
• Antidote for curare or curare-like agents (neuromuscular blockers) to reverse the effects of certain medications used during surgical procedures
• Not recommended for maintenance therapy in myasthenia gravis due to short duration of action
• Was previously used to terminate supraventricular tachycardia, but has been replaced by other antiarrhythmic agents

Learn about indirect-acting anticholinesterase, reversible AChE inhibitors, and their mechanisms of action on acetylcholinesterase enzyme and acetylcholine receptors.