[Exacerbation of pseudoparalytic myasthenia gravis following azithromycin (Zithromax)]

We report the case of a 25-year-old female patient with severe aggravation of myasthenia gravis due to azithromycin which was prescribed for an influenza syndrome. One hour after the intake of 500 mg azithromycin the patient developed weakness of the legs and respiratory distress due to respiratory muscle failure. She was hospitalized in a comatose state and required intubation and mechanical ventilation for six days. Acute worsening of myasthenia gravis was observed in this patient in 1986 after parenteral administration of erythromycin. Erythromycin causing aggravation of myasthenia gravis by interfering with neuromuscular transmission is reported in the literature. The close temporal relationship between the intake of azithromycin and severe worsening of myasthenia gravis in our patient suggests that azithromycin, a new azalid-antibiotic of the macrolid group, can exacerbate myasthenia gravis. We conclude that azithromycin should be added to the list of drugs to be used with caution in patients with myasthenia gravis.