Evaluation of Medication Exposure on Exacerbation of Disease in Patients With Myasthenia Gravis

Background and Purpose: In patients with myasthenia gravis (MG), worsening of symptoms poses a risk of respiratory failure which can be precipitated by medication use. Although purported, the risks associated with administration of certain medications are not fully elucidated. Thus, clinical decision support involving a best practice alert was executed to caution providers of drug-disease interactions when ordering a potentially harmful medication. We performed an analysis of the alert overrides with subsequent medication exposure to determine the incidence of MG exacerbations.Methods: This retrospective chart-review evaluated adult patients with MG at 2 large academic medical centers via electronic health records between November-2019 and November-2021 who received a medication following override of the clinical decision support tool. The primary outcome was proportion of patient encounters complicated by myasthenic exacerbations after potentially harmful medication administration. Secondary outcomes included changes in motor strength, length of stay, discharge disposition, unplanned level-of-care escalations, and changes to immunosuppressant therapy following medication administration.Results: A total of 70 orders were assessed in 38 patients across 55 encounters. Medications administered during these encounters included macrolides, fluoroquinolones, beta-blockers, calcium channel blockers, and magnesium sulfate. Exacerbation of disease occurred in 7 patient encounters (12.7%) and occurred after intravenous magnesium or intravenous labetalol. In 5/7 events, at least 1 other risk factor associated with a myasthenic exacerbation was present.Conclusions: Of the medications reported to potentially worsen MG, intravenous labetalol and intravenous magnesium were the 2 agents associated with myasthenic exacerbations with a higher incidence in patients harboring additional risk factors.