Medications to Avoid When You Have LEMS

Emily Malcolm, PhD avatar

by Emily Malcolm, PhD |

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LEMS and medications

Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disease that primarily affects nerve cells and muscles. The immune system mistakenly attacks a specific component of the nervous system that controls muscle contractions. This results in muscle weakness, among other symptoms.

There are some medications that you should not use if you have LEMS, as they can make your symptoms more severe. However, if your disease is well-controlled, your doctor may prescribe some of these medications, especially to treat acute problems like infections.

You should always be watchful for symptoms with any new medication, and contact your doctor if they worsen.


Doctors frequently prescribe antibiotics to treat infections. Some antibiotics can worsen LEMS symptoms because they have neuromuscular blocking effects. However, an infection can sometimes be worse. Your primary care physician will weigh the risks and benefits when prescribing a particular antibiotic.

The antibiotics that are most likely to cause problems with LEMS are very strong antibiotics given by injection in the hospital.

Ketek (telithromycin) is one antibiotic that doctors should never prescribe for patients with LEMS or other myasthenic conditions, as it has been associated with fatalities.

Heart medications

Doctors treat some heart conditions, as well as high blood pressure, with medications called beta-blockers. These medications can exacerbate symptoms of muscle weakness in myasthenic conditions because they affect neuromuscular transmission.

Medications used to treat neurological disorders

A wide range of medications are used by doctors to treat neurological disorders, some of which may interfere with nerve function. It is important to discuss the risks of new medications with your physician, including a discussion of symptoms or changes that you should be watching for.


Last updated: June 1, 2020


Lambert-Eaton News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare providers with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.