Pyridostigmine for myasthenia gravis

Sounds like 'pir-ID-oh-STIG-meen'

Key points about pyridostigmine

  • Pyridostigmine is used to improve muscle strength in the treatment of myasthenia gravis.
  • Pyridostigmine is also called Mestinon.
  • Find out how to take pyridostigmine.
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Pyridostigmine is used to improve muscle strength in the treatment of myasthenia gravis. Myasthenia gravis is a long term condition that causes your muscles to weaken and tire easily. 

Pyridostigmine works by preventing the breakdown of acetylcholine in your body. Acetylcholine is needed for normal muscle function because it helps electrical signals travel between the nerves and muscles. Learn more about myasthenia gravis.

In Aotearoa New Zealand pyridostigmine is available as tablets (60 mg).

  • The dose of pyridostigmine is different for different people, depending on your condition.
  • You doctor will usually start you on a lower dose and increase it slowly, depending on your symptoms.
  • Pyridostigmine works quickly (within 30 minutes) and the effect lasts for up to 4 hours. You're most likely to have this medicine prescribed to be taken every 3 to 4 hours. It's best taken at times when strength is needed, such as before getting out of bed and before meal times.  
  • Always take pyridostigmine exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it and any special instructions.

  • Timing of your dose:  You can take pyridostigmine with or without food. Swallow the tablets with a glass of water. If you have problems swallowing the tablets, they may be halved or crushed. Ask your pharmacist for advice. 
    Pyridostigmine works quickly (within 30 minutes) and the effect lasts for up to 4 hours. You're most likely to have this medicine prescribed to be taken every 3 to 4 hours. It's best taken at times when strength is needed, such as before getting out of bed and before meal times.  
  • Missed dose: If you forget to take your dose, take it as soon as you remember. But if it's nearly time for your next dose, take the next dose at the right time. Don't take extra doses to make up for a forgotten dose. 

Here are some things to know when you're taking pyridostigmine. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Other medicines: Pyridostigmine can interact with some medicines, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting pyridostigmine and before starting any new products.
  • Avoid or limit alcohol while you are taking pyridostigmine. Alcohol can increase your chance of side effects, such as flushing and tiredness.
  • If you are having an operation or dental treatment, tell your healthcare provider that you are taking pyridostigmine. Pyridostigmine can interfere with some medicines used during surgery.
  • Pregnancy: Tell your doctor if you're pregnant, planning to become pregnant, or breastfeeding.

Like all medicines, pyridostigmine can cause side effects, although not everyone gets them. Often side effects improve as your body adjusts to the new medicine.

Side effects What should I do?
  • Feeling sick (nausea)
  • Being sick (vomiting)
  • Stomach cramps
  • Runny poo (diarrhoea)
  • Increased saliva (drooling)
  • Increased sweating
  • Agitation
  • This is quite common when you first start treatment or when you increase your dose.
  • Tell your doctor if they don't go away.


For more information on side effects, see the more information section below or the consumer leaflet(external link) that comes with the product.

Read more about medicines and side effects and reporting a reaction you think might be a side effect.

References

  1. Mestinon(external link) Consumer Medicine Information, Medsafe NZ
  2. Pyridostigmine(external link) New Zealand Formulary

Brochures

Medicines and side effects
Healthify He Puna Waiora, NZ, 2024

5 questions to ask about your medications

5 questions to ask about your medications

Health Quality and Safety Commission, NZ, 2019 English, te reo Māori

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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