Hi, everyone. I am doing very well with the MG, but I am having a flare-up of my Graves' disease (autoimmune hyperthyroidism), which had been in remission for six years. For many reasons, I don't want to kill my thyroid with radioactive iodine. But I have read that methimazole and other thyroid suppressants can worsen MG permanently. I took methimazole for the first time for a few months in the spring of 2009 (I had always used PTU before that--I've had Graves' for almost 20 years). I came down with my first MG symptoms in the fall of 2009 (after a short bout with H1N1). There may be a connection.

Does anyone have any knowledge or ideas about how to deal with this? My neuro isn't knowledgeable about Graves', and my endo isn't knowledgeable about MG. Thanks.

Abby

I would choose the RAI. An out of whack thyroid really messes everything up. I had RAI over 5 years ago for Grave's disease. I would choose it again. My MG didn't start until three years ago and they kept trying to blame it on my thyroid. With the thyroid irradiated,you only have to worry about minor adjustments for your thyroid meds. The antithyroid meds started to destroy my liver so I had no choice but do RAI.

Stellatum, from a PubMed search ("methimazole myasthenia gravis") I can't see any evidence that taking methimazole is a risk factor for making MG worse.

Obviously, discuss this with your clinical care team but the (lack of) evidence suggests that taking methimazole, if you decide to do that, should not be an issue for you as far as MG is concerned.

Thanks, both of you. The last time I took methimazole, I took it for less than three months, and got six years of total remission out of it. If you use thyroid suppressants for long enough, they can send you into permanent remission. I think there's a good chance I'm two months' worth of methimazole away from cured--my endo had hoped that my previous flare would be my last.

That's one reason I don't want to do the RAI if I don't have to. Another is that I'm not confident I'll ever be happy with how I feel on synthroid. And even if I eventually get it right, I'm terrified of the months of being hypo. I have a ton of people depending on me. I can't afford to check out even temporarily--I'm afraid of the fatigue, and terrified of the possibility of depression. I think I would never recover from that no matter what my numbers said.

Here are the links I found about the methimazole-MG connection. They're just case reports, but one of the articles suggests a mechanism by which methimazole may have an immuno-modulatory effect. Because I got MG after taking methimazole, I'm especially wary.

http://www.ncbi.nlm.nih.gov/pubmed/20635587
http://www.ncbi.nlm.nih.gov/pubmed/22957965
http://www.ncbi.nlm.nih.gov/pubmed/1798220

Here's a case report of methimazole causing more autoimmune problems in someone who has Graves and MG:

http://www.jscimedcentral.com/Geront...ogy-2-1021.pdf