Key takeaways

  • Dosage for Mestinon depends on the form you’re prescribed and the severity of your myasthenia gravis. The drug comes as a liquid solution, tablet, and extended-release tablet. Your doctor will likely start you on a low dosage and adjust it over time to reach the right amount.
  • With the liquid solution or tablet, the typical Mestinon starting dosage range is 60 to 360 milligrams (mg) per day.
  • The recommended dosage of the extended-release tablet is one to three tablets (180 to 540 mg) once or twice per day.

Mestinon (pyridostigmine) is approved to treat myasthenia gravis in adults.

The active ingredient in Mestinon is pyridostigmine. (An active ingredient is what makes a drug work.) It belongs to a group of drugs called cholinesterase inhibitors.

This article describes the dosages of Mestinon, as well as its strengths and how to take it. To learn more about Mestinon, see this in-depth Mestinon article.

Your doctor will likely start you on a low dosage and adjust it over time to reach the right amount for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly prescribed or recommended for myasthenia gravis. Always take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs. In some cases, doctors may adjust your dosage from those shown here.

The following information describes Mestinon dosage forms and strengths. Continue reading for details about dosages for myasthenia gravis.

Mestinon forms

Mestinon comes in three oral forms:

  • liquid solution
  • tablet
  • extended-release (ER) tablet

The liquid solution and tablets are immediate-release (IR) drugs. This means that they release the drug into your body right away. On the other hand, ER tablets slowly release the drug into your body over a long period of time.

Mestinon strengths

Mestinon comes in different strengths depending on its form:

  • Liquid solution: 60 milligrams per 5 milliliters of solution (60 mg/5mL)
  • Tablet: 60 mg
  • ER tablet: 180 mg

For treatment of myasthenia gravis, your doctor may recommend that you combine different Mestinon forms. For example, they may suggest that you take the liquid solution in the morning when swallowing is more difficult and then switch to the tablets later in the day once the medication has started to work. They may also recommend a combination of IR and ER forms to manage your symptoms more effectively.

IR tablet and liquid solution: A typical starting dosage of IR Mestinon is 60 to 360 mg per day. This dosage will be divided into smaller doses to be taken throughout the day.

Depending on how your body responds to the medication and your symptom severity, your doctor may prescribe a higher Mestinon dosage. On average, adults with myasthenia gravis take 600 mg of IR Mestinon in divided doses throughout the day.

ER tablet: If you’re prescribed Mestinon ER tablets, the typical dosage is one to three tablets (180 to 540 mg) once or twice per day. If you’re taking two doses per day, each dose should be separated by at least 6 hours.

The maximum dosage of Mestinon is 1,500 mg per day. The maximum dosage is for all forms of Mestinon combined.

Always follow your doctor’s instructions. Notify them if you experience any side effects that may prevent you from taking your medication.

All forms of Mestinon are swallowed. They can be taken with or without food. But taking Mestinon with food may decrease the risk of certain side effects, such as nausea and abdominal cramps.

Mestinon IR and ER tablets can likely be split. They have one or two lines dividing the tablet into sections, which makes them easier to split. But the drug manufacturer hasn’t provided information about whether Mestinon should be split, chewed, or crushed. Talk with your doctor if you have questions about splitting, chewing, or crushing Mestinon tablets.

If you have trouble swallowing tablets, talk with your doctor about the liquid solution form. You can also read these tips for taking tablets.

How long do you take Mestinon?

Mestinon is usually a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take it long term.

What if you miss a dose?

If you miss a dose of Mestinon, talk with your doctor.

Your Mestinon dosing schedule is personalized for you. Your treatment plan may include both IR and ER forms that release the drug into your body at different times. This makes missing a dose more complicated. That’s why it’s important to talk with your doctor if you miss a dose.

If you need help remembering to take your dose of Mestinon on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Do not take more Mestinon than your doctor prescribes, as this can lead to harmful effects.

Symptoms of Mestinon overdose

An overdose of Mestinon may cause a cholinergic crisis. This is a serious condition that can lead to death. Symptoms of a cholinergic crisis include:

What to do in case you take too much Mestinon

Call your doctor right away if you think you’ve taken too much Mestinon. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

The following are answers to some commonly asked questions about Mestinon’s dosage.

Is Mestinon’s dosage similar to the dosages of Rituxan?

No, Mestinon and Rituxan (rituximab) come in different forms and have different dosing schedules.

Mestinon comes in forms that you swallow, and is taken several times per day.

Rituxan is a liquid solution given as an intravenous (IV) infusion (an injection into a vein given over time) by a healthcare professional in a doctor’s office or clinic. The dosing schedule for Rituxan depends on the condition it’s being used to treat.

However, myasthenia gravis is an off-label use of Rituxan, and drug manufacturers don’t provide dosage information for off-label uses. (An off-label use is when a medication is used for a purpose other than what it’s approved for.) That said, studies of Rituxan have shown it to be a safe and effective treatment for myasthenia gravis, so talk with your doctor if you’d like to learn more about Rituxan.

How long does it take for Mestinon to start working?

Immediate-release forms of Mestinon start to work within 15 to 30 minutes after you take a dose. But it may take a couple of weeks for you and your doctor to determine the best treatment regimen for you.

If you have questions about what to expect from your Mestinon treatment, talk with your doctor.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.