Levothyroxine and AFib

[jeanette1952]

I had blood work done twice to check (and then recheck to make sure) that I had hypothyroidism  My first reading was 5.6.  She then ordered the full thyroid screen including T3 ad T4 profiles and put me  on 25 mcg of Levothyroxine daily.  I don't know the level in last blood test. I took the first one today.  I had an episode of AFib one year ago (anxiety related).  On this dosage I was told chances are very low that it will bring on AFib. I am very anxious about this as that is one experience I do not want to repeat as it is dangerous. What are my chances of getting AFib on this low dose? I do take medication to keep down anxiety.

[goolarra]

I responded on your new thread.

[jeanette1952]

I just received my latest results in the mail.  Labs were taken 6/11/2015.

TSH           4.932       Range: 0.350 - 4.500     uIU/ml   (Ultrasensitive)
Free T4      1.04         Range:  0.80 - 1.80        ng/dl
Free T3       2.7           Range:  2.3  -  4.2         pg/ml

Since starting the Levothyroxine I am constipated (was not before) and my right hip is really starting to hurt, I have been on it for 3 weeks.  Should I be on it at all? I have not felt good since starting this medication. Note: My TSH was 5.6 (taken on 5/7/2015) on previous test taken just one month before. I was on NO medication before either one of these TSH tests were taken (Levothyroxine). There were no results for Free T3 and Free T4 on the first test because no test were done on these until 6/11/2015.

[goolarra]

Let me first re-iterate gimel's question:  Can you call your doctor and get the results of the T3 and T4 tests with reference ranges?

It takes the initial dose of Synthroid, or any dose change, 4-6 weeks to reach its full potential in your blood.  In the meantime, your FT3 and FT4 levels are building.  25 mcg is a low starting dose, which is good since you have a history of heart arrhythmia.  The low dose will give your body time to adjust to the higher levels of thyroid hormone.  It would be unusual to see any big changes in symptoms this early.  Furthermore, the initial dose we are put on is seldom the dose we end up on, especially when the initial dose is kept low in consideration of other health issues.  After about four weeks, you should be retested for FT3, FT4 and TSH and adjust meds.  Once again, to lessen the possibility of arrhythmia, you want to continue to increase slowly.  

If you post your T3 and T4 results, we can see how low your T3 and T4 were and how far you have to go to get your levels where they should be.  

[gimel]

T4 has a half life of about one week.  That means that it takes a week for serum level to reflect 50% of the dose increase.  Then it goes up to 75 % the second week.  That assumes nothing else is affected; however, many hypo patients find that as they start on thyroid med, their TSH will be diminished and in return their production of natural thyroid hormone is also diminished, with the overall result that their total serum levels of T4 and T3 don't really rise for a while.  So I would not be concerned about the 25 mcg of T4.  

We really need to have a look at your biologically active thyroid hormones, which are Free T4 and Free T3.  That will provide a much better look at your thyroid  status than the TSH test.  Were you tested for Total T4 and T3 or Free T4 and T3?

How about Vitamin D,  B12 and ferritin?

[jeanette1952]

How long does it usually take for levothyroxine 25 mcg to start working? I have been on it for six days now and no noticeable changes yet.  I am constipated and fatigued...these are really my only symptoms. Just want to know the average time it takes to kick in.  

[gimel]

Please post your thyroid related test results and reference ranges shown on the lab report.  That will better enable us to assess your status and answer your questions.  Also, if tested for Vitamin D and ferritin, please post those as well.  Also, please tell us about any symptoms you are having.