Why are macrolides (macrolide antibiotics) contraindicated in patients with Myasthenia Gravis (MG)?

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Last updated: April 24, 2025View editorial policy

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From the FDA Drug Label

Exacerbation of symptoms of myasthenia gravis and new onset of myasthenic syndrome have been reported in patients receiving azithromycin therapy.

Macrolides are not recommended in patients with myasthenia gravis because they may exacerbate symptoms of the disease or trigger new onset of myasthenic syndrome, as reported in patients receiving azithromycin therapy 1.

From the Research

Macrolide antibiotics should be avoided in patients with myasthenia gravis due to the potential risk of worsening muscle weakness and triggering a myasthenic crisis, as suggested by the most recent study 2. The use of macrolides in patients with myasthenia gravis is a concern due to their potential to exacerbate the disease.

  • The exact mechanism of this interaction is not fully understood, but it is thought to be related to the inhibition of acetylcholine receptors at the neuromuscular junction, which is already compromised in myasthenia gravis patients 3.
  • Specific macrolides to avoid include azithromycin, erythromycin, clarithromycin, and telithromycin, although the risk may vary among these medications 4.
  • If antibiotic treatment is necessary for patients with myasthenia gravis, alternative classes such as penicillins, cephalosporins, or tetracyclines should be considered when appropriate for the infection being treated 5.
  • It is essential for patients with myasthenia gravis to be aware of the potential risks associated with macrolide antibiotics and to seek immediate medical attention if they experience increased weakness after taking these medications. Some studies have investigated the association between macrolide antibiotics and myasthenia gravis exacerbation, but the evidence is not yet conclusive 5. However, given the potential risks, it is recommended to exercise caution and avoid using macrolides in patients with myasthenia gravis whenever possible, as supported by the most recent and highest quality study 2.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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