Do You Need To Avoid Certain Medications When You Have Myasthenia Gravis?

If you have myasthenia gravis (MG), your team may have warned you that some common medications can affect how well your muscles work.

“Many medications can exacerbate myasthenia gravis symptoms,” says neurologist Georgette Dib, MD. “That doesn’t mean you can’t ever take them. We just need to manage them more carefully.”

Knowing what may cause problems — and when to talk with your healthcare provider — can help you stay safer and avoid unnecessary flare-ups.

Why some medications affect myasthenia gravis

MG disrupts communication between your nerves and muscles, and certain medications and supplements can further complicate things.

The effects can range. Some medications can add to fatigue. Others can have more serious symptoms, like worsening troubles with swallowing or breathing.

That’s why it’s important to tell every healthcare provider you see that you have MG — especially before starting a new medication or having surgery.

“You want providers to know about your condition so they can choose medication accordingly,” Dr. Dib states. “We recommend that people with myasthenia gravis carry a medical ID card or wear a medical alert bracelet. That way, even in an emergency, they can get the treatment that’s safest for them.”

Medications that may worsen myasthenia gravis

Some people will tolerate certain medications well, while others may find they worsen their symptoms.

Still, Dr. Dib says there are several medication categories that deserve extra caution. She shares some common ones.

Magnesium

Magnesium is often a big concern for people with MG.

“Magnesium can worsen myasthenia and exacerbate symptoms by working on the neuromuscular junction,” Dr. Dib explains. In other words, high doses of magnesium can exacerbate the already-troubled communication between your nerves and muscles.

The biggest offender is intravenous (IV) magnesium. It’s sometimes used in hospitals for conditions like preeclampsia, heart rhythm issues or severe magnesium deficiency.

Some people may tolerate over-the-counter magnesium supplements in small doses. But Dr. Dib advises avoiding them unless your healthcare provider specifically recommends them, especially if your myasthenia symptoms aren’t well managed.

She adds that magnesium may hide in over-the-counter products, like:

• Laxatives
• Antacids
• Multivitamins and other combined supplements

Unless your provider says otherwise, you shouldn’t need to worry about magnesium naturally found in foods.

“You’re unlikely to eat so much magnesium-rich foods that it affects your condition,” Dr. Dib clarifies. “But it’s certainly easy to get too much when you take supplements.”

Antibiotics

Certain antibiotics are known for worsening MG symptoms. They include:

• Fluoroquinolones, like ciprofloxacin (Cipro®), which is often used for urinary tract infections and respiratory issues
• Macrolides, like azithromycin (Z-Pak®), commonly prescribed for respiratory infections
• Aminoglycosides, like gentamicin, which is typically used for more serious bacterial infections, like sepsis and meningitis
• Penicillin can be used to treat a range of bacterial infections, including strep throat, ear infections and more

If you have an infection that needs antibiotics, your provider may recommend other ones if they’re likely to do the trick. But sometimes, even the antibiotics that aren’t necessarily recommended for myasthenia gravis are still your best treatment option.

“If the medication is needed, especially for infections, we manage the myasthenia symptoms while treating the infection,” Dr. Dib explains.

Beta-blockers and calcium channel blockers

Beta-blockers and calcium channel blockers are medications used to treat high blood pressure and heart rhythm conditions. And they may worsen muscle weakness in MG.

But they’re common medications. And lots of people, including people with myasthenia gravis, need them to help manage their heart health.

In those cases, your provider will work with you to treat your heart while balancing risks carefully.

“There are ways to lower the impact on MG symptoms,” Dr. Dib says. “If they’re needed, we can adjust your MG treatment and monitor symptoms closely.”

Statins

Statins are medications used to lower cholesterol. They can worsen, or even cause, MG symptoms.

“Very rarely, statins can either trigger myasthenia gravis, or people can get myasthenia symptoms for the first time from statins,” Dr. Dib says.

But if you need statins, there are ways to lower the risk. Providers may recommend:

• Starting with a lower dose
• Combining lower-dose statins with other cholesterol medications
• Monitoring symptoms carefully

Botox

Botulinum toxin injections (Botox®) can be risky for people with MG.

“We definitely recommend avoiding Botox because it’s a neuromuscular blocker,” Dr. Dib explains. That means Botox blocks nerve signals to your muscles. In people with MG, this can significantly worsen weakness and other symptoms.

Botox is perhaps best known for its cosmetic uses. But it’s also used as treatment for a range of concerns, including:

• Spasticity
• TMJ pain
• Overactive bladder
• Excessive sweating
• Migraines

If you have myasthenia gravis, your providers can recommend other treatments for these conditions.

Certain anesthesia medications

Certain anesthesia medications can also create risks for people with MG. Some muscle-relaxing drugs used during surgery may dangerously worsen breathing problems.

When appropriate, local anesthetics are often safer options. Medications like propofol and sevoflurane, for example, are relatively safe in myasthenia gravis.

If you need to be fully sedated, make sure your anesthesiologist and surgeon know you have myasthenia gravis.

Supplements and herbal remedies

Over-the-counter herbs and supplements may seem harmless. But they’re loosely regulated and Dr. Dib says most haven’t been studied well in people with MG.

“I don’t personally recommend supplements,” she states. “There’s just too much we don’t know about them.”

She advises extra caution with:

• High-dose zinc supplements
• “Immune-boosting” products
• Herbal blends or mushroom-based supplements
• Products containing quinine

“There’s always the risk of toxicity or worsening myasthenia symptoms,” she continues. “The benefits don’t outweigh the potential risks.”

If you’re considering adding a supplement to your routine, discuss it first with your healthcare providers.

Final thoughts

The list of medications to avoid with myasthenia gravis can be long. And it’s complicated. There are a lot of nuances and considerations to be made when choosing the right medications.

Never stop or avoid prescribed medications on your own because of MG concerns. Instead, talk with your neurologist, pharmacist or other healthcare provider if:

• You’re starting a new medication.
• You notice worsening weakness.
• You develop swallowing difficulties.
• You feel more short of breath than usual.

With careful monitoring and communication, you can rest assured that you’ll safely receive the treatments you need to manage your health, not just your MG.