What to Expect When Starting Mestinon for Myasthenia Gravis

Medical Disclaimer: This content was created for generalized informational purposes only. This is not intended to be a substitute for professional medical advice, diagnosis, or treatment.

Pyridostigmine (Mestinon) is a drug used to treat muscle weakness in myasthenia gravis (MG). Though Mestinon is often prescribed for MG, patients still might have questions about what to expect when starting this treatment.

When will Mestinon start working?

When taken orally, pyridostigmine starts working within 15-30 minutes and its effects last for 3-4 hours. Patients usually start to feel much better 2 hours after administration.

How do doctors determine the dose?

The dosing schedule of pyridostigmine is different for every patient and can be adjusted over time as symptoms of myasthenia gravis change. For example, a patient with a hard time chewing or swallowing may only need to take pyridostigmine before meals. A patient with severe weakness may need higher doses throughout the day.

A typical starting dose is 30 MG 3 times per day. After several days of starting pyridostigmine, patients should note whether they are having side effects - commonly diarrhea, stomach cramps, nausea, slowed heart rate, excessive salivation or sweating.

These are not all the possible side effects a patient may have. If a patient is having bad side effects, they should talk to their doctor as the dose or amount can be reduced.

Additionally, medication being taken with food can help lower stomach upset and more medications that help side effects can be introduced. If a patient is ok with pyridostigmine but still having myasthenia symptoms, the dose or amount can be increased with guidance from their doctor.

If a patient reaches the highest daily dose of pyridostigmine without getting less symptoms, or they find side effects too bothersome, their doctor will likely suggest stopping pyridostigmine and starting immunomodulating therapy.

How can I cope with side effects of Mestinon?

Every patient has a different amount of side effects they can tolerate. In general, life-threatening side effects mean you have to stop. If non-life-threatening side effects are causing lots of distress, discomfort, or are affecting daily functioning, then stopping or dose lowering is advised.

If side effects are mild, not too bad, and come with good symptom control, then staying on the med is reasonable.

How to keep track of symptoms from Mestinon

Patients should report any new symptom to their doctor, even if they are not sure if it is related to their medication. Be strict in reporting side effects of pyridostigmine. These can include stomach upset, diarrhea, excessive salivation/sweating, slowed heart rate, and muscle cramping.

Between appointments, it is important to keep track of what time of day your myasthenia symptoms flare and how well pyridostigmine is helping your symptoms. This information will help your doctor craft the best dosing schedule for you.

For example, you may notice that your symptoms are worse in the afternoon but well controlled in the morning - this can make your doctor to increase your afternoon dose.

Should I talk to my doctor about Mestinon?

I'm a doctor, so my role is to present medication options to my patients, explain their risks and benefits, and provide an objective opinion. If a patient is unsure if a medication is right for them, I encourage them to voice their questions and concerns to their doctor and start a conversation.

Be honest and do not worry about asking silly questions. Ultimately, the decision to start a medication is a personal choice, but exchanging information with their doctor doctor will help patients make the most informed decision possible.