Why have I been prescribed this medication?

Pyridostigmine is used in myasthenic disorders to improve muscle strength.

How it works

Pyridostigmine (brand name Mestinon) is one of the most common medicines used to treat myasthenia symptoms. It is an AchE (Acetylcholinesterase) inhibitor, also known as an anticholinesterase. Acetylcholinesterase is the enzyme responsible for breaking down Acetylcholine. In patients with myasthenia, Acetylcholine is unable to bind to its receptor due to blockage by autoantibodies. By reducing levels of the enzyme responsible for breaking it down, Pyridostigmine increases the amount of free Acetylcholine in the body and therefore increases the rate of successful interaction.

How it is delivered

Pyridostigmine is available in tablet and syrup (oral) form. Tablet-form Pyridostigmine can also come in a sustained-release version (SR) upon special request from your neurologist, which can be useful at bedtime for patients symptomatic during the night or in the early morning. The dose of pyridostigmine depends on your needs. The typical maximum dose is six tablets (each 60 mg) a day, divided up to be taken several times during the day. If you feel you need more than the usual dosage range, please seek the advice of your neurologist. In children, the dosage is dependent on weight.

When you have it and how long you will be taking it

Pyridostigmine is generally taken up to every 4 hours during daytime hours, but this may vary based on advice from a neurologist and the type of medication prescribed. It takes around 30 minutes for the dose to take effect. Continue to take pyridostigmine as prescribed even if you feel well and do not stop taking this medication without consulting your neurologist.

Side Effects

All medicines can cause unwanted side effects which usually improve as your body adjusts to the new medicine. Some of the common side effects you may experience are:

  • upset stomach
  • diarrhoea
  • vomiting

Some adverse side effects include:

  • severe itching
  • skin rash
  • hives

If you experience any of these symptoms, please call your doctor immediately.

Please check the patient information sheet supplied with your medication for a more detailed list of possible side effects. If any side effects disclosed concern you, seek reassurance from your doctor or the team at myaware for more information.

Known UK suppliers



  • Can I take pyridostigmine with Buscopan? Based on advice from our medical committee, it is indeed safe to take both pyridostigmine and Buscopan.
  • Do Pyridostigmine tablets contain lactose? Yes, pyridostigmine tablets contain lactose.
  • Can I break up my Pyridostigmine tablets? If you have trouble swallowing tablets, Pyridostigmine can be halved or quartered. They can also be crushed to a fine powder and added to water.
  • Can I take pyridostigmine while pregnant? There remains to be more studies regarding the effect of pyridostigmine on pregnancy, and your doctor will advise you on the balance of benefits and potential harm to your baby. Pyridostigmine does not cross the placenta barrier. There have been indications that only negligible amounts of pyridostigmine are excreted in breast milk. Please consult your doctor if you plan to breast feed while taking pyridostigmine.
  • What is a cholinergic crisis? Too high a dose of anticholinesterase drugs can make a patient weaker again. It can be difficult to distinguish between a cholinergic crisis and a myasthenic flare up. Therefore, it is important to closely monitor your symptoms when increasing your dose of pyridostigmine.
  • How do I store Pyridostigmine? Store pyridostigmine in a closed container in a cool dry place and protect from sunlight.

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