Azathioprine as a single immunosuppressive drug in the treatment of myasthenia gravis.

We retrospectively evaluated results obtained from azathioprine (AZA) treatment on a selected sample of 40 patients affected by autoimmune myasthenia gravis (MG). Patients received AZA as a single immunosuppressive drug for at least 2 years. Twenty out of 40 patients received also a one-month course of cyclophosphamide (CP) before starting AZA. All patients started immunosuppressive treatment out of myasthenic crisis. After 3, 12 and 24 months of AZA treatment, 82.5%, 92.5% and 97.5% of the patients respectively showed improvement in functional state, disappearance of bulbar involvement, or both. The impressive percentage of short-term positive results did not seem influenced by pre-treatment by CP. Side effects included only minor and transitory gastrointestinal symptoms and reversible cytopenia. Although the patient population was either particularly suitable for AZA treatment or candidate to a better response, our data suggest that AZA might also have good short term effects in a subgroup of MG patients.