Therapeutic Monitoring of Azathioprine Metabolites in myasthenia Drs Rae and Pinto, Southampton This study is hoping to improve the management of patients with myasthenia gravis. Azathioprine is a drug commonly used for the treatment of myasthenia gravis. However, patients often experience different responses to azathioprine, some with good symptom control, others with less improvement ans as azathioprine often takes a while to produce an optimum effect this could mean that some patients maybe badly controlled for some time. This project hopes to be able to predict from simple blood tests who will response and who will not so that treatments can be changed earlier if needed. We are currently recruiting patients with myasthenia from Wessex Neurological Centre Southampton to test their blood, alongside routine blood tests, for levels of azsthioprine. So far 6 patients have been enrolled into the ongoing study. The aim is to initially recruit 20-30 patients with myasthenia. It is hoped that the study will be expanded to other Neurologial departments in the future.