Mestinon is a valuable therapy in the early stages of MG. It was a miracle drug for me. It opened my eyes, ended double vision and allowed me to drive again. It made me functional for the many months is took for an immunosuppressant to begin working. But Member 7721 is wise in his warning. Once your other drugs are working, Mestinon can cause a toxic buildup of acetylcholine and mind blowing cramps. Screaming cramps. The kind of cramps your whole neighborhood can hear. I will always love Mestinon for its early-stage benefits. But I don't touch the stuff today.