Hello Jessica
My personal experience is that Imuran is very successful in controlling my MG. Having started after diagnosis a few months ago on a high dose of Mestinon, then IVIg when in respiratory crisis, prednisolone and Imuran were added. The pred is being slowly reduced as the Imuran becomes more effective. I take Mestinon now "as needed" which is only when I have more than usual physical activity, either before or after, 15 - 30 mg. I take 100 mg Imuran daily and at the moment 12 1/2 mg pred. The only noticeable side effect I have is weight gain due to pred, and none that I can attribute to Imuran. I take supplementary calcium and vit D to offset bone loss. My neuro says all is going to plan and I will be back to "where I was before" by the end of the year, just on Imuran. So for me it seems to be effective. I will be glad when I'm finally off the pred but for the moment am glad to be on it while it's doing its job as I'm virtually symptom free unless I do more than usual and get very tired (then rest is as good as medicine). Maybe I've just been lucky.
Best wishes
Marian