Pyridostigmine
MestinonPubChem CID 4991 · 3D model
Drag to rotate. Scroll or pinch to zoom.
Blocks the enzyme that breaks down a nerve-signaling chemical, so more of it lingers at the junction between nerves and muscles, helping weak muscles contract better.
How it works
Pyridostigmine blocks an enzyme called acetylcholinesterase, whose normal job is to quickly break down a chemical messenger, acetylcholine, that nerves use to tell muscles to contract. In myasthenia gravis, the immune system attacks and reduces the docking points nerves use to deliver that message to muscles, so signals get through poorly and muscles tire and weaken easily. By slowing the breakdown of acetylcholine, pyridostigmine lets more of it build up where nerves meet muscles, helping the weakened signal get through and improving muscle strength. It's similar to an older drug called neostigmine but lasts longer and causes fewer stomach side effects. Because too little or too much of the drug can both cause worsening weakness, doses need to be carefully adjusted for each patient.
What it’s used for
Pyridostigmine is used to treat myasthenia gravis, an autoimmune disease in which the immune system attacks the connection points nerves use to signal muscles, causing muscle weakness and tiredness that gets worse with activity and better with rest. It helps improve muscle strength, including muscles used for eye movement, speech, swallowing, and breathing, and can be taken long-term to manage ongoing symptoms. Because both too little and too much medication can cause muscle weakness, the dose has to be carefully tailored to each person, and doctors need to be able to tell the difference between the disease itself getting worse and the medication causing too strong an effect.
- Mechanism
- Acetylcholinesterase inhibitor
- Drug class
- Small molecule
- Therapeutic area
- Neuromuscular