Synthroid Dosage

[Debbie6865]

I had radioactive iodine to kill my thyroid gland a few years ago.  I've been taking Synthroid for the hormone now.  Apparently I was on too much med for a while.  I found another doctor and now I'm wondering if I'm too low.  I have some muscle weakness (I get muscle cramps in my lower legs by my ankles with just trying to briskly walk a mile -- this has not been a problem for me before), a burning icy-hot sensation in my arm, ALL my teeth hurt the other day ?, my heart has been racing a bit more lately.  I woke up in the middle of the night a few nights ago with my heart racing, and feeling a lot of nervousness, almost like I could pass out.  The feeling subsided in about 15-20 minutes.  I weigh 132 pounds.  My doctor right now acts like the med is prescribed by weight.  I've never heard of this.  My TSH and T3 and T4 were checked about 3 weeks ago and of course they are in the "NORMAL" range.  Ugh.  I HAD been taking 125mcg as of last March and then this doctor knocked the dose down to 100mcg.  It helped a lot at the time, but now I'm wondering if it may be too low.  She doesn't want to change anything.  Thank you for your viewpoint.

[Barb135]

It appears that your doctor might be basing her judgement on the TSH, which most people would consider "perfect", even though TSH is an indicator, at best.  Your FT4 is quite low in the range and apparently, she's not testing FT3 at all.  

"Rule of thumb" (doesn't apply to everyone) is that FT4 should be about mid range and FT3 should be in the upper 1/3 of its range.  Your FT4 is only at 36% of the range and we have no idea about FT3, so we don't know if you are converting the FT4 to FT3 adequately or not.

You should ask for the FT3 test, next time you get TSH and FT4; if she refuses, you should probably find another doctor, because one who refuses to look at FT3, and/or doses based on TSH, will keep you very ill.

[Debbie6865]

When I first interviewed my current doctor she said she would always look at symptoms, not just labs.  The expected range on my lab report for TSH is 0.5 - 4.7 and Free T4 expected range is 0.73-1.95.  

[Debbie6865]

No... I've thought about that too!

[Debbie6865]

My TSH is 1.5 and my Free T4 is 1.17

[Totie]

Dosage in my opinion is not based on weight. I am 200mcg and only weigh 100 lbs. After my TT, I was started on 125mcg & then I only weighed 88 lbs.

Can you find another Endo who will go by symptoms as well as lab tests?

[Brucergoldberg]

also have you had a sonogram or an uptake since the RAI to make sure that everything was okay after the RAI?

[Ericamegan]

Hi, I had RAI 21/2 years ago. Afterwards I became hypo and had bad muscle cramping, racing heart, anxiety.  I had many drs who said my levels were fine, but they were not right for me.  Please post labs, so we can help.

[goolarra]

Please post your actual lab results and include reference ranges.  Ranges vary lab to lab and have to come from your own lab report.  

Initital dose of meds is prescribed by weight (when there's nothing else to go on).  However, once on meds, it isn't further adjusted by weight, but by lab vales and, most of all, symptoms.  Or I should say, it should be adjusted by FT3, FT4 levals and symptoms.