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Synthroid starting dose 125 mcg

RAI killed my thyroid, I am starting on 125 mcg Synthroid.  According to most posts, that is an unusually high starting dose.  I've learned it is calculated by weight at 1.7 mcg/kg/day.  So, 125 mcg of Synthroid would be for 160 lb. person, which I am (thanks to being hypo for two weeks!).  This is my second day on that dose.  When will I know it is too high?  Does anyone take a dose that high?  My endo started the Synthroid when my labs were:

TSH      21.04    (.3 - 5.5)
FT3         1.8     (1.9 - 3.9)
FT4           .32    (.76 - 1.70)

I am also sensitive to drugs, so I'm afraid this dose will be way to high for me.  When should I have another blood test? Any advice?

Thanks, Sandy
15 Responses
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Avatar universal
How do you find a doctor to up your meds? Mine had half of her thyroid removed and is on 50 mcg of synthroid and I had all of mine removed and she wont put me on any higher than 100 mcg of synthroid, I am tired all the time and am gaining a lot of weight, I used to weigh 105 now weigh 140 and climbing and it has only been 3 months since surgery!!
Helpful - 0
Avatar universal
I had TT due to thyroid cancer, then RAI.  At that time my TSH was 186, my doc started me at 150 mcg.  I was a very active person before the TT, so I guess I need more.  I have been uped twice, and now am on 1875 mgc...seems high, but that is where I am now feeling normal, and am back to running/walking a few miles every day.  I still have 5 or 6 pounds to go, so I am obviously not taking too much.  It is still a struggle to lose the weight, but at least now I feel like I can get through a day without a couple glasses of iced tea.
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Avatar universal
I am just diagnosed with hypo after being hyper 15 years ago..all went normal and i stopped the meds 10 years ago.  Got checked 3 years ago and all was still fine.  Last month I was diagnosed as hypo with tsh of 108! Yikes!  Synthroid made me crazy and doc wouldnt do anything.  He looks about 25 and isnt very sure of himself but I am very informed from my research and books and internet so I am guiding him in my treatment.  He is open to my findings and will test whatever I ask him to do.  I had a doc when I was hyper and he was very good but wouldnt listen to me about my symptoms or anything and my treatment was brutal until I finally adjusted my meds on my own by how I felt.  I miraculously got better and he took all the credit.  This is much better.  He is not a great doc but we have tested for any complications and ruled them out so I feel comfortable in have some say in my treatment.  I insisted on a beta blocker as this is what I took when I was hyper and it gave me my sanity back.  He agreed after I educated him on WHY I was having such a reaction to the synthroid.  My body has had none of the thyroid hormone for so long and I am so SEVERLY hypo that I need to get used to the meds slowly and he needs to treat the symptoms that they cause.  Its almost fun teaching him and I intend to email him this forum so he can read that I am not the only one which is how he made me feel at first.  Thank you for everything you all share.  Love and Prayers to all of you!
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Avatar universal
Smilerdeb is right on the target when saying WE'RE ALL DIFFERENT and we ALL RESPOND TO THYROID MEDS DIFFERENTLY.

Hang in there, and be patient.  Adjusting and readjusting any thyroid med is normal and takes time and patience, as well as constantly questioning your doctor about your symptoms.

After my RAI, I started on 200 mcg of synthroid (my endo refuses to prescribe generics, I asked for the generic synthroid once, and I could tell the difference almost immediately...so went back to the name brand), I now take 175 mcg of synthroid and 10 mcg of cytomel.

I also have heart disease and have to watch for any cardiac problems with my thyroid meds.  My doctors and I have been messing with both my thyroid meds as well as all of my cardiac meds since the RAI...it's a pain in the butt, since we all want to simply feel "NORMAL," but to feel normal again takes time.
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Avatar universal
I would say the sore legs is still Hypo Sandy and it may take a while for the TSH to come down. Baby steps is what we have all had to do....I used to get so sick of people say 'BE PATIENT' but in actual fact, it is true.
If you rush the dosage , you will go hyper within no time at all.
I have a good Doctor (forget my Endo, she was fired after the 2nd visit lol)who did bloods on me every week for 4 weeks then when I hit just over 6.0 on the TSH, he did bloods weekely for me so as to get some idea as to what was going on.
These labs graduated to fortnightly after about 4 weeks on Thyroxin and then 3 weekly.
I still have bloods done 2-3 weekly as if I wait the 6 weeks, I would be up the creek without a paddle lol.
I had the flu some time ago and went hypo again but my levels are good at the moment.
My Doc says that until I have gone 3 months on a steady level, to keep continuing the blood tests.
I have in the past gone from hypo to hyper in 2 weeks flat but increasing my dose too much and had to start from scratch all over again.
So........ slowly does it is the secret to wellness.
If you have a cr@ppy day....just remember that tomorrow is another day.
Write down yr dosage each day, your symptoms and yr pulse rate.THEN watch a pattern emerge.
From that , when the time comes to 'tweak' your meds, it will be a lot easier.
They say the minimal time to regulate is usually about a year and my anniversary is on the 27th of this month.
Take Care...you will be fine.
If the legs hurt too much, a warm bath or a 'heat pack on the legs ease the pain.


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Avatar universal
Thank you to all of you for your input.  I hadn't checked the site for several hours and was pleasantly surprised to read so many experiences!  You surely are right, everyone reacts differently.

One more symptom that occured in the early morning hours after two 125 mcg tablets of synthroid was that my legs hurt so much that there was no more sleeping for me.  I hope that cutting the dose down will help with that,  although, they ache right now.  I've read that hypo causes muscle soreness also.  But I've been hypo for probably close to two weeks and didn't have soreness until I took the synthroid.

My endo said that medication for hypo after RAI was easier to control than Graves with Tapazole.  It's only been three days now, and I question that assumption!  Without a thyroid, I (we) HAVE to have replacement drugs, and if we can't tolerate them very well, then we are bsically up a creek without a paddle for life.

Since my thyroid is completely dead now, do any of you think that starting out with 31 mcg's is too small of a dose?  How long should I stay on that dose before a blood test? Two weeks long enough?   Or should I slowly increase the dose to 62 mcg's, which is half the dose my endo had me start on, but was too much for me, and then get blood work?  He really doesn't give me as much direction as I'd like.  I read and study and try to figure out what I should do, then email him about it.  He's two hours away and treats me long distance.  I have standing blood work orders here in town with my family doctor, and they are faxed to the endo.  Anyway, I'm thankful he emails me with some direction. I see him in person twice a year as I have progressed from Graves, to RAI, to hypo.

I wish endos would read these posts, it sure would help to educate them and make them better doctors for all of us.

Thank you to everyone.  Maybe someday I can help others who are new to all of this like I am.
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Avatar universal
See how everyone is different?
This is what people have to understand.
Just because Joe Blogs is on ??/ dosage and Jill Blogs is on ??? dosage....we are all very different.
But it does help when people put the effort in to post their stories so as other people can relate to it all.
I think without this site, I wouldnt have had a clue where to start when dx with Graves.

I thank each and every one of you who have helped me on my 'journey'.

I always said from the start...Peace of Mind isnt far away...its only a journey.
Well Ive found that peace of mind, Ive travelled that journey and will still continue to travel it but as time goes on.....I have less baggage (more knowledge and support).
It does get easier, believe me.
Good Luck to everyone on their "journey" :)
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Avatar universal
I was on 200 mcg after TT. I weighed 100lbs, I stayed on that for 12yrs. Now I am on 125mcg and weigh 97lbs.
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Avatar universal
When I started on levo, my TSH was 64.  After about two weeks on 88, I doubt FT3 and FT4 had change significantly (I know I wasn't hyper), but I sure had reacted to the meds like I was.

If the quarters aren't exactly even, I wouldn't worry too much.  Just cut one pill at a time and finish it before moving on to the next one.

I agree with Smilerdeb...you want to keep a close watch on what's going on in case you react to the drug very quickly.    

I haven't had any hypo symtoms since very shortly after I went on levo.  It seems that as long as my FT3 barely makes it into normal range, I'm fine.  Even at 25 mcg, I felt great (except for the tachy)!  And the increases to 75 have not made me feel any different. Of course, I have Hashi's, so I'm probably still chasing a moving target as I continue to lose thyroid function.  But I don't know that for sure, and it seems the increases didn't do a lot but increase side effects.
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Avatar universal
By The way......I am 122 lbs (just over 60 kgs) and am only on 62.5mcg daily.
I have only just gone to this dose the last 4 weeks.
I had RAI a year ago for Graves, Hyperthyroidism, A-Fib and Thyca...followed up by a TT 3 months later (Sept 08).
Prior to that I was on 62.5mcg 4 times a week and 50mcg 3 times a week ....so be very careful and watch your symptoms.
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Avatar universal
Why did your Doctor let you get so high in the TSH?
Normally you are monitored and start a T4 med when the TSH is between 6.0 and 10.0.
Watch you dont head Hyper very fast.
I am super drug sensitive and can go hyper to hypo within 2 weeks flat.
As this is just the start of you taking T4 med, I would be getting bloods done every 2-3 weeks at the beginning.
This at least gives you an idea if the med is working fast.
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Avatar universal
I contacted my endo and told him I was having problems, and could I half or quarter the 125 mcg Synthroid.  He was okay with halving it.  Well, I'm going to quarter it and slowly increase it.  The quarters aren't exactly even, but I will have to make due that way.

It helps to know that the symptoms from too much Synthroid can behave like hyperthyroidism, but not BE hyperthyroidism.  That helps make sense out of what I'm feeling.  I've explained to my endo in the past that I always need the smallest amount of any drug I take for whatever, but I guess he missed that part.

How long would you recommend I stay on a particular dose?  Let's see, a quarter of 125 mcg would be about 31 mcg's per day.  It probably won't make much of a change in the actual FT 3 and FT 4 figures, though, will it?  At your low tolerated dose, does it keep you out of hypothyroidism?

I appreciate your information, it does help me understand what is happening and what is needing to be done.

Thanks, Sandy
Helpful - 0
1 Comments
I don’t understand why you were told to cut your pill. According to my doctor, pharmacologist and the company, the med in the pill is small and not evenly dispersed. Your chances of getting any or all of what you need is very hit and miss.
Avatar universal
If you start out at too high a dose, or increase too rapidly (for YOU...it's all very individual), you don't have to BE hyper to have hyper symptoms.  I hope that makes sense!  Your labs can be normal or even hypo, but you get hyper symptoms because your body has not acclimated to the meds.

I'd say you qualify as over 50, with a history of arrythmia.  I'd definitely ask your doctor about starting out more slowly. Your dose may eventually get up to 125mcg, but it doesn't pay to rush it.

It is a guessing game...gets very frustrating at times.

I have a congenital heart defect that makes me susceptible to tachycardia.  My PCP, when I asked directly, told me that there was NO way that levo would exacerbate my arrythmia unless I got hyper.  WRONG!  Two weeks later, and I was having tachy multiple times a day.  Backed down to 44mcg, another two weeks, multple tachy again.  Down to 25, and finally I saw a cardio and got on a beta blocker to control the tachy.  Then, I was able to increase my levo dose very slowly (to 75, which took over a year!).  I am on a stable dose for the moment and still haven't gotten back up to the 88 mcg my PCP had started me on (and doubt I ever will).  It was not a fun time.  I still can't believe how clueless she was when it came to thyroid.
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Avatar universal
Thank you for your comments and information.  I am 62 years old and have atrial fib ONLY when I am hyperthyroid from Graves, which I won't be any more except if the Synthroid dosing gets too high.

Maybe I'll check into taking half of what I'm taking now, just to be safe.  I imagine my endo prescribed such a high dose because I am so hypo now.  125 mcg's sure are a lot higher than the 25 mcg's that many people take.  I am having the "brain fog" that hypo produces, and am very tired.  So, maybe I need the dose to be that high.  I don't know.  The whole thing from the beginning, with Tapazole for Graves, has been a huge guessing game.  I went for blood tests more often than normal because I knew my thyroid was changing quickly -- both on Tapazole and as the thyroid became more hypo.

What side effects did you experience at 88 mcg's and still at 25 mcg's?

Thanks for your help.  Sandy
Helpful - 0
Avatar universal
If you know that you are sensitive to meds, the dose could be a bit high to start (I'm not a doctor).  However, as a maintainance dose, 125 mcg is not at all unusual.

Your labs are seriously hypo, and your doctor probably wants to get your FT3 and FT4 up fairly quickly.

Signs of overmedication or too high a starting dose can include:  anxiety, heart palpitations and/or tachycardia, insomnia, high BP, restlessness, etc.  They're basically the same as hyperthyroid symptoms.  If you start to feel any of these, call your doctor to get your dose reduced.

However, if you're concerned about starting that high and know you're sensitive to meds, you might not wait for symptoms and just tell your doctor you're more comfortable starting out slowly.  Ask him if you can take half until your first labs.

You should repeat labs in four to six weeks.

If you're over 50 or have a history of heart arrythmia, the recommended starting dose of Synthroid is 12.5 to 25 mcg.  (Don't know if either of those apply.)

I'm extremely meds sensitive.  My PCP started me on 88 mcg.  I ended up having to back down to 25 and still had side effects.  It would have been much better to start out low and move up slowly.  You don't feel better quite as fast at the beginning, but in the long run, slow and steady is a lot more comfortable.

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