Azathioprine in the treatment of myasthenia gravis.

Twenty-four patients with myasthenia gravis were treated with azathioprine. Eighteen of the patients tolerated the drug. Six discontinued azathioprine therapy because of toxicity. Of the 18 patients, 15 (83%) improved while receiving azathioprine; in 8 (44%) improvement was felt to result solely from azathioprine. Initial response was seen after 4 to 10 months of treatment, with a mean of 6.4 months. Patients continued to improve for up to 24 months, with the mean time of peak improvement being 14 months. Relapse occurred within one year in all 6 patients in whom azathioprine administration was discontinued. Azathioprine is a reasonable alternative to corticosteroids in selected myasthenic patients requiring immunosuppression.