Mestinon side effects: What you should know

Mestinon can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Mestinon in clinical trials:

• nausea and vomiting
• diarrhea
• abdominal cramps
• muscle cramps or twitching
• muscle weakness

Mild side effects can occur with Mestinon. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Mestinon’s prescribing information.

Mild side effects that have been reported with Mestinon include:

• nausea and vomiting
• diarrhea
• abdominal cramps
• increased saliva and mucus
• pinpoint pupils
• sweating more than is typical
• muscle cramps or twitching
• muscle weakness
• skin rash
• symptoms of increased peristalsis (wave-like muscle contractions that move food through your digestive system)*
• mild allergic reaction†

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Mestinon and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Mestinon. However, it’s not clear whether this side effect occurred in clinical trials. To learn more, see the “Side effect specifics” section below.

Mestinon may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Mestinon’s prescribing information.

If you develop serious side effects while taking Mestinon, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

• Cholinergic crisis (a condition caused by too much Mestinon in the body)*
• Severe allergic reaction.†

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Mestinon. However, it’s not clear whether this side effect occurred in clinical trials. To learn more, see the “Side effect specifics” section below.

Mestinon may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Can Mestinon cause long-term side effects?

Mestinon isn’t known to cause long-term side effects. To learn about side effects of Mestinon, see the “Mestinon side effects” section above.

Talk with your doctor if you have questions about your risk of side effects with Mestinon.

Do side effects of Mestinon go away?

Most likely. Some of the most common side effects of Mestinon, such as nausea, diarrhea, and abdominal cramps, may be temporary as your body adjusts to the drug.

If you continue to experience bothersome side effects, talk with your doctor. They may recommend ways to manage side effects. Your doctor also may adjust your dose to help lessen side effects. Any side effects you experience will typically go away quickly after decreasing or stopping the drug.

It’s important that you do not stop taking your medication without talking with your doctor first. Stopping the medication or skipping too many doses can cause you to experience significant muscle weakness.

If you have any questions about side effects with Mestinon, talk with your doctor.

Learn more about some of the side effects that Mestinon may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Mestinon.

Increased peristalsis

Symptoms of increased peristalsis were a commonly reported side effect of Mestinon in clinical trials. Peristalsis is the wave-like muscle contractions that move food through your digestive system. Symptoms may include:

• diarrhea
• abdominal cramps
• frequent bowel movements
• heartburn
• difficulty swallowing

What you can do

If you have symptoms that don’t go away or are bothersome or serious, talk with your doctor. They may adjust your dose or recommend additional ways to manage these side effects.

Cholinergic crisis

Although it’s rare, Mestinon can cause a condition called cholinergic crisis. This can happen from taking too much Mestinon. Symptoms may include:

• increasing muscle weakness
• difficulty breathing due to weakening of muscles involved in breathing

It’s important to recognize that the symptoms of cholinergic crisis may be difficult to distinguish from myasthenic crisis (worsening of myasthenia gravis).

What you can do

If you notice any symptoms of cholinergic crisis, contact your doctor immediately. They can determine what changes to your treatment plan are necessary.

Allergic reaction

As with most drugs, Mestinon can cause an allergic reaction in some people. However, it’s not clear whether this side effect occurred in clinical trials.

Symptoms can be mild or serious and can include:

• skin rash
• itching
• flushing
• swelling under your skin, typically in your eyelids, lips, hands, or feet
• swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Mestinon. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Mestinon. This drug may not be the right treatment option for you if you have certain medical conditions or other factors that affect your health. These include:

Asthma. If you have asthma, talk with your doctor before taking Mestinon. They may monitor you more closely during treatment with the drug.

Blockage of intestines or bladder. If you have or have had any type of blockage in your intestines or bladder, tell your doctor. They will likely recommend that you do not take Mestinon.

Kidney problems. After you take a dose of Mestinon, your kidneys help remove the drug from your system. If you have kidney problems, such as chronic kidney disease, this may be harder for your body to do. Your doctor may prescribe a lower dose of Mestinon.

Allergic reaction. If you’ve had an allergic reaction to Mestinon or any of its ingredients, your doctor will likely not prescribe Mestinon. Ask your doctor what other medications may be better options for you.

Pregnancy or breastfeeding. It’s not known whether it’s safe to take Mestinon if you’re pregnant or breastfeeding your child. Mestinon has not been trialed in pregnant people or people who are breastfeeding. Talk with your doctor before taking Mestinon.

Alcohol consumption. There are no known interactions between Mestinon and alcohol. Talk with your doctor or pharmacist if you have questions about drinking alcohol while taking Mestinon.

Most side effects from taking Mestinon tend to be mild. You should talk with your doctor if you have any side effects that last, bother you, or are serious.

If you’d like to learn more about Mestinon, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

• More information about Mestinon. For details about other aspects of Mestinon, refer to this article.
• Cost. If you’d like to learn about Mestinon and cost, see this article.
• Dosage. For information about the dosage of Mestinon, view this article.
• A look at myasthenia gravis. For details about your condition, see our list of generalized myasthenia gravis articles.

Disclaimer: Medical News Today 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.