UMEM Educational Pearls

Category: Neurology

Title: Medications in Myasthenia Gravis

Keywords: Myasthenia gravis, myopathy, iatrogenic (PubMed Search)

Posted: 1/29/2015 by Danya Khoujah, MBBS
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Patients with myasthenia gravis (MG) may be seen in the emergency department for symptoms that are not related to their MG, such as an upper respiratory tract infection or chest pain, for example.

The emergency physician should be careful in prescribing new medications to patients with MG, as that can precipitate a myasthenic crisis (and therefore cause significant morbidity and mortality). Below is a list of medications that are commonly implicated; an extensive list can be found on

  • Iodinated IV contrast
  • Fluoroquinolones
  • Aminoglycosides
  • Macrolides
  • IV magnesium replacement
  • Beta blockers (metoprolol and labetalol)


Sanders DB, Guptill JT. Myasthenia Gravis and Lambert-Eaton Myasthenic Syndrome. Continuum. 2014 Oct;20(5)