Myasthenia Gravis Treatments/Medications and Procedures

Over-the-Counter Medicines and Myasthenia Gravis: Which Are Safer to Take?

Medically reviewed by LilyAnn Jeu, Pharm.D.

Written by Jazmin N. McSwain, Pharm.D., BCPS

Posted on October 28, 2026

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Key Takeaways

People with myasthenia gravis (MG) need to take extra care when choosing over-the-counter (OTC) medicines, since some common ingredients may worsen symptoms of this nerve and muscle condition.
The Myasthenia Gravis Foundation of America keeps a list of cautionary drugs that could worsen MG symptoms, and a recent study found that people with MG who took medicines on this list were more likely to experience worsening symptoms. Ingredients like magnesium found in antacids and laxatives, first-generation antihistamines in sleep aids and cold medicines, and certain pain relievers may all affect MG in different ways depending on a person's overall health.
Reading the active ingredients on OTC medicine labels, keeping a list of all medications to share with your healthcare team, and checking with a pharmacist or doctor before trying any new OTC product or supplement can help people with MG make safer choices.

View all takeaways

A headache, allergy symptoms, or a cold can send you looking for over-the-counter (OTC) medicine to relieve your symptoms. However, if you have myasthenia gravis (MG), it’s important to check the ingredients before heading to the register.

Some OTC medications for pain, allergies, or a cold may contain ingredients that could worsen myasthenia gravis symptoms, while others may be safe. Knowing what to look for in OTC ingredients can help you make a safe, informed choice.

This article explains how OTC medicines can affect myasthenia gravis, which OTC medications to consider, and how to choose an OTC medication safely.

🗳️ What’s your biggest concern when choosing over-the-counter (OTC) medicine with myasthenia gravis?

Finding a medicine that won’t worsen my symptoms

Knowing which ingredients to avoid

Avoiding interactions with my current medications

How Over-the-Counter Medicines Can Affect Myasthenia Gravis

Myasthenia gravis is an autoimmune disease that affects how nerves and muscles communicate. It does this by causing the immune system to mistakenly attack nerve-to-muscle signaling, which can lead to muscle weakness and fatigue over time.

Some medications can also interfere with this process and worsen muscle weakness. Because of this, the Myasthenia Gravis Foundation of America (MGFA) maintains a list of cautionary drugs that could worsen myasthenia gravis symptoms, including some OTC medications.

In fact, a recent study found that people living with myasthenia gravis who took medications on this list were more likely to have worsening myasthenia gravis symptoms.

However, that doesn’t mean that every person with myasthenia gravis must never take these medications. The MGFA advises people with myasthenia gravis to always check with their doctor or pharmacist before starting a new medication, even OTC medicines.

Common OTC Medicine Categories To Consider

OTC medicines come in many forms and under many brand names. The right choice depends on the ingredients, dose, and your overall health history.

Pain and Fever Medications

If you have pain or a fever, you may find yourself in the aisle, wondering, “Can you take Tylenol with MG?”

Tylenol is the brand name for acetaminophen, a common pain-relieving and fever-reducing drug. Similarly, nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen or naproxen, are also commonly taken for aches and pains.

Neither category should automatically be considered universally safe or unsafe for everyone living with myasthenia gravis. The right choice depends on your other health conditions and medications.

For example, NSAIDs may not be a good choice for people with kidney or heart problems or who have had a stroke or heart attack. Acetaminophen may not be safe for people with certain liver problems.

This is why it’s important to always check the active ingredients of any OTC product.

If you’re not sure which pain or fever medication to take, ask your pharmacist or healthcare provider. They can tell you which OTC medicines are safe for you based on your health conditions and other medicines you take.

Cold, Allergy, and Sleep Products

Although OTC cold, allergy, and sleep medicines aren’t listed as cautionary drugs for myasthenia gravis, they still have side effects and ingredients to watch for.

Antihistamines

Antihistamines can relieve allergy symptoms and may also help with a runny nose from a cold. Some, however, can cause drowsiness, which you may want to avoid if you already have weakness or fatigue from myasthenia gravis.

Decongestants

Decongestants are commonly found in some OTC cold medicines. They can affect blood pressure and heart rate, so if you have a history of hypertension (high blood pressure), talk to your pharmacist or healthcare provider before taking them.

Over-the-Counter Sleep Aids

OTC sleep medicines or “nighttime” cold medicines usually contain antihistamines as an active ingredient because some antihistamines can cause drowsiness. First-generation antihistamines (like diphenhydramine and doxylamine) also have direct effects on nerve-to-muscle signal transmission, meaning they may directly worsen myasthenia gravis symptoms.

If you already have muscle weakness or fatigue, consider that before taking an OTC sleep aid.

Antacids, Laxatives, and Supplements

Medications used to treat heartburn and constipation may seem unrelated to myasthenia gravis. However, the ingredients in antacids, laxatives, and even supplements still matter.

Some of these OTC products contain magnesium, and current MGFA guidance warns that high doses of magnesium may worsen myasthenia gravis symptoms. Magnesium may be found in laxatives, antacids, and as an ingredient to help form solid tablets in other medications.

Despite this, magnesium is still commonly prescribed to people living with myasthenia gravis. Sometimes, it’s simply overlooked on an ingredient list.

For example, you may take a multivitamin or herbal supplement and think that it’s safe because it’s OTC. However, OTC supplements may contain active ingredients, such as magnesium, that could interact with your medications or affect your myasthenia gravis.

This doesn’t mean every herbal product will worsen myasthenia gravis symptoms. Still, it’s best to check the active ingredients and talk to your pharmacist or healthcare provider before taking any new OTC products or supplements.

How To Choose an OTC Medicine Safely

Choosing an OTC medicine may feel overwhelming at first, but you don’t have to memorize every medicine that could affect your condition. A few simple steps can make choosing an OTC medicine easier.

Look for Active Ingredients

Avoid relying on a product’s brand name. Turn the OTC product over and read the Drug Facts label. This label shows the product’s active ingredients.

If the product contains magnesium, or another ingredient listed on MGFA’s cautionary drug list, ask your healthcare provider if you should take it.

Watch for Combination Products

Many cold, allergy, flu, and sleep products may have the same or similar active ingredients. Taking several products with the same ingredient can increase your risk of adverse effects.

Consider Your Other Health Conditions

If you have high blood pressure or problems with your heart, kidneys, or liver, you may need to avoid some OTC medicines. Your healthcare provider can tell you which OTC medications to avoid.

Ask a Pharmacist To Check for Interactions

Keep a list of your prescription and OTC medicines. Bring your medication list to any medical appointments so your healthcare team knows what you’re taking.

A pharmacist can also review your medication list to check for interactions with OTC medicines.

When To Contact Your Healthcare Team

If you start taking an OTC medicine, watch for changes in your usual myasthenia gravis symptoms. Call your doctor immediately if you notice any new or worsening muscle weakness, difficulty swallowing, chewing, or speaking. Call emergency professionals if you notice any of the following:

Severe shortness of breath or difficulty breathing
Severe swallowing problems
An inability to walk or talk, or worsening symptoms

Swallowing or breathing problems can signal a myasthenic crisis. This can be life-threatening. Don’t wait for symptoms to become severe. Seek medical attention right away.

Key Takeaways

Not all OTC medications or supplements are unsafe for people with myasthenia gravis, but some, such as magnesium supplements, may worsen muscle weakness or interact with other medications.

Beyond staying up to date on the MGFA cautionary list, the biggest takeaway is to read ingredient labels carefully. An OTC medicine’s safety depends on its active ingredients, dose, other medications, and your overall health.

If you’re unsure about a medication’s safety, ask a pharmacist or your healthcare provider. If you take medication and develop new or worsening muscle weakness or have difficulty swallowing or breathing, seek emergency care right away.

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