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What's the mechanism of action for Mestinon (pyridostigmine)?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on April 1, 2025.

Official answer

by Drugs.com

Mestinon works by slowing the breakdown of the chemical messenger acetylcholine at the neuromuscular junction. This action helps to improve muscle strength by increasing the signals between nerves and muscles. Mestinon is a prescription medication used in the treatment of myasthenia gravis, a neuromuscular disease.

Our muscles need acetylcholine to function well. Mestinon affects the chemical messengers in the body that are involved in the communication between nerve impulses and muscle movement.

  • Mestinon (pyridostigmine) works by increasing levels of acetylcholine (ACh), a chemical messenger (neurotransmitter) found in our bodies.
  • It does this by preventing the acetylcholinesterase (AChE) enzyme from breaking down acetylcholine in the neuromuscular junction (especially in muscles and nerves), thus leading to increased levels.
  • Greater levels of acetylcholine lead to higher neuronal transmission across the neuromuscular junction.

Why is Mestinon prescribed?

Mestinon (pyridostigmine) is classified as a reversible acetylcholinesterase inhibitor. It is useful in the treatment of myasthenia gravis, a long-term, autoimmune, neuromuscular disease characterized by weakness and fatigue of skeletal muscles (the muscles that allow body movement in the arms and legs, and for breathing).

Myasthenia gravis can affect people of any age, but is more common in women younger than 40 and in men older than 60.

There's no cure for myasthenia gravis, but treatment can help relieve signs and symptoms such muscle weakness, double vision, drooping eyelids, and difficulties with speech, chewing, swallowing and breathing.

Pyridostigmine may also be used to reverse the effect of non-depolarizing neuromuscular blocking medication and can be used in military personnel who have been exposed to nerve gas.

This is not all the information you need to know about Mestinon (pyridostigmine) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

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