Thyroid Disorders Community
25.9k Members
Avatar universal

connection between synthroid and myasthenia gravis

My husband is taking Synthroid for hypothyroidism.  He is 63 and his thyroid seems to have taken early retirement.  Suddenly, after being on Synthroid for about 3 months, he began to develop symptoms of Myasthenia Gravis.  He is having difficulty swallowing (back of tongue is not working) and his lips become numb and hard to control after he speaks for about a minute.  Resting the muscles in his lips allows him to talk normally until the muscles fatigue again, after about a minute.  Has anyone else developed MG or MG-like symptoms after starting Synthroid?  I found two sites on the Internet that mention this as a rare side effect of this drug.

Thanks so much.

This discussion is related to Synthroid Side Effects.
5 Responses
125112 tn?1217277462
I am not up on medication and possible side effects. For starters, he should have his TSH and Frees tested. From what I understand, most feel better at a TSH level of about 1.00 or little less.
That said, if your husband has Hashimotos Hypothyroidism (auto-immune conditon) the chances of developing another auto-immune disorder is greater and M.G. is an auto-immune disorder. You and your husband should discuss this with his doctor. It certainly warrants further investigation. Sorry to hear he is experiencing these symtoms. I can imagine how distressing this must be for you both.

Avatar universal
George doesn't have Hashimoto's.  He doesn't have any autoimmune disorders that we know of.  We don't know why his thyroid simply stopped functioning.  His doctor says that this sometimes happens with age (but George is only 63).  He is having a battery of tests this week.  He saw a speech therapist on Monday, and he is having a barium swallow study and cat scan tomorrow, and a neurology consult on April 10.  We need to find out what is happening to him; he definitely has MG-like symptoms.  I strongly suspect that the medication is responsible for the symptoms because the thyroid problem was corrected by the Synthroid, and George should not be developing hypothyroidism symptoms at this late date, when his thyroxine level is normal.

I'll let people know what we find out.  
Hi im wondering what happens to your husband, going through a similar situation witt my mom I think it's from taking synthroid and not ocular MG... can you please contact me I'm having trouble finding others that have experienced this and it would be helpful to know what the result was for your husband thanks so very much
125112 tn?1217277462
If you haven't done so already: you should request copies of his blood labs. Did George have thyroid antibody testing (TgAb=Thyroglobulin Antibody and TPO=Thyroid Peroxidase Antibody)? These are the tests that reveal auto-immunity against the thyroid.

It sounds like he is on his way to finding out the problem re: tests. I'm glad that the doctors are thoroughly investigating this.

As for thyroid, sometimes adjustments need to be made in meds or a change in them-however, to the latter, I usually hear complaints about the generic version and not the name brand.

It will be interesting to hear what you find. I truly hope this is a temporary/remedied situation.

All my best,
Avatar universal
Thanks so much for the info about the tests specific to autoimmunity against the thyroid.  I will ask my husband and his doctor if he has had these two tests.  Obviously, he needs them.  Will keep you posted.

125112 tn?1217277462
I wrote you a personal message.
Have an Answer?
Top Thyroid Answerers
649848 tn?1534637300
Avatar universal
1756321 tn?1547098925
Queensland, Australia
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
We tapped the CDC for information on what you need to know about radiation exposure
Endocrinologist Mark Lupo, MD, answers 10 questions about thyroid disorders and how to treat them
Smoking substitute may not provide such a healthy swap, after all.
How to lower your heart attack risk.
Trying to lose weight? Grab a snack that works with your diet, not against it. Check out these delicious, slimming foods.
Trying to lose weight? Grab a snack that works with your diet, not against it. Check out these delicious, slimming foods.