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Switching from Levothyroxine to Synthroid

  I’ve been taking the generic Levothyroxine for about 11 yrs and then I went to see an endo for the first time and he switched me to Synthroid and now I feel horrible.  My symptoms are all over the place; hungry but then feel sick after eating, burning feeling in hands and feet, tired, dizzy,brain fog, just an overall ill feeling.  These symptoms started 5 days after starting Synthroid.  Could the sudden switch bring on these symptoms?
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Avatar universal
Before commenting on your latest labs I need to know what time of the day did  you take the Tirosint, and what time was  blood was drawn  for the tests.   As for your response to elevated FT3/FT4, what reactions/symptoms does it cause for you?  Also, do you have any remaining symptoms currently on the Tirosint?  Have you been tested for Vitamin D, B12 and ferritin?
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I always take Tirosint upon waking, but never on scheduled lab day's.  Labs were done approx 7:30-8am,.  I convinced Endo to try Tirosint, cause I read Tirosint works especially well for those that had TT.  No, symptoms on Tirosint, nerves, shaking, tremors, muscle spasm, etc.... all gone.  I'm on 2000iu Vit D, B12 and Ferritin normal.  But, I can explain more in detail via pm.      
Avatar universal
I think if you read the following link it will put your mind at ease regarding generics.  

testedhttps://www.fda.gov/drugs/generic-drugs/generic-drug-facts

Note the following:   "A generic drug is a medication created to be the same as an existing approved brand-name drug in dosage form, safety, strength, route of administration, quality, and performance characteristics."

That is not to say that the fillers and binders used in manufacture are the same.  They are not, in all cases, and can be the source of different effects noticed by patients.  If you find a good brand that works for you it is a good idea to stick with that brand.    Anytime you seem to notice a difference in result when switching meds such as going from a T4 to NDT,  you should evaluate the dosages to make sure they are equivalent.  Frequently doctors use the wrong conversion factors.  Also, if test results are "bouncing around" , was the time between taking the med dose and the blood draw for tests comparable?  If not that can cause different test results.  

AJWS6    Tirosint is a hypoallergenic T4 med in liquid form.   As such it is reported to be more absorbable.  Absorption can also be affected by when you take the med and whether you were fasting at that time.  What was the dosage of Levo/Synthroid and also Tirosint?  Also what were your Free T4 and Free T3 levels  with Levo/Synthroid compared to Tirosint?

Turtle67    What are your Free T4 and Free T3 levels and reference ranges shown on the lab report?   What is your daily dose of Synthroid?  You have no symptoms?
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3 Comments
Hi Gimel, I'd have to write a book explaining my hormone med experience.  On Levo/Synthroid I was bounced around from 162mcg-275mcg.  On Tirosent I've been stable on 125mcg for a year, then increased to 137mcg a few weeks ago.  My labs last week.  For some odd reason, my body does not like elevated FT3/FT4.
TSH 1.9 (.34-5.6)
FT3 3.0 (2.5-3.9)
FT4 .98 (.57-1.64)
So these were all she ordered last lab that I have results for. A week ago I pushed for more lab work and FT3 to be added. I am only taking 37.5mcg of synthroid.  I have been dealing with severe burning ankles and feet with swelling for 2 years. It went away for a week when I switched to synthroid but it is back today, though on as bad. Since the whole switch from Levo to amour and back to levo 2 years ago, I have gained 25 pounds and deal with thyroid symptoms.  I keep being told it is fibromyalgia. I am still waited for an endo appointment. I can deal with everything but the burning and inflammation in my ankles. It is so bad I can't wear shoes at times and nothing helps it.  I upped my vit D3  even though my doctor said no. My levels are borderline low. I have been tested for everything under the sun and nothing seems to be wrong so I am told it is Fibromyalgia. I don't accept that.
T4,Free(Direct) 0.82-1.77   1.75
TSH 0.450-4.500                2.950
Nor should you just accept that it is fibromyalgia.    That is a name given  to a collection of symptoms for which there is no specific cause.    It often seems to be something they seize on when unable to identify causes for symptoms that are often related to hypothyroidism.  

You don't necessarily need an Endo.  Frequently they specialize in diabetes, not thyroid.  Also they tend to pay attention mostly to TSH, and not symptoms.  That is very wrong.  If they go beyond TSH they typically will test for only Free T4, and then  use Reference Range Endocrinology, by which they will tell you that a FT4 test within range means you don't have a thyroid problem, that you symptoms must be due to something else.   That is very very wrong.

What you need is a good thyroid doctor that will treat clinically,  and test and adjust Free T4 and Free T3 levels as needed to relieve hypo symptoms.   Many of us have found that we required Free T4 about mid-range, and Free T3 in the upper part of its range, adjusted as needed to relieve symptoms.    You may find that you need to add a source of T3 to your med in order to achieve adequate levels of Free T3.   When taking thyroid med, TSH should never be used to titrate the med dosage.  

it is important that you always test for Free T4 and Free T3 every time you go for tests.   Also, you should be tested for cortisol at the beginning of treatment to assure it is optimal.    Hypo patients are also frequently deficient in Vitamin D, B12 and ferritin so those should be tested and supplemented as needed to optimize.  D should be at least 50 ng/mL, B12 in the upper part of its range and ferritin should be at least 100.

If you have problems getting those tests done, you may find good use of the one page Overview of a paper on Diagnosis and Treatment of Hypothyrodism: A Patient's Perspective.  To find the paper click on my name and then scroll down to my Journal and read at least the  Overview.    If your doctor resists doing the tests and does not want to treat clinically, for symptoms, then you will need to find a good thyroid doctor that will do so.
Avatar universal
There is a difference in some of the inert ingredients. I started getting a rash when they upped my Levothyroxin so they changed me to Synthroid. I didn't have a rash with that but for the few week or so I had awful joint pain. I decided to try the Levothyroxin again because of the cost of Synthroid. (I have no insurance) This time around I have not had a rash.
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2 Comments
I had a similar issue. I was switched from Levothyroxin to Amour. The first few weeks I felt like a million bucks but then I started getting burning ankles and feet, extreme joint pain and fatigue. I was switched back to Levothyroxin and the  problems continued. For almost 2 years I have been told it was just Fibro. Finally I got a doctor to take it seriously and switched me to Synthroid. So far no Symptoms!  Fingers crossed this will continue.
I certainly can relate Turtle67, I was on Levo had horrible symptoms, then switched to Synthroid, horrible symptoms, both meds had my labs bouncing all over the place, then switched to Tirosint, problem solved.  I haven't had a reaction to Tirosint nearly a year and my labs are stable.  Not all meds are created equal.    
315318 tn?1353251800
Why did the Dr increase your dose from 75 mcg to 87 mcg ?
Can you get Synthroid in 75 mcg dose ?
In my opinion, the generic levo and the one you get from Synthroid should be the same. Your symptoms are highly indicative of Thyroxine "overdose" and I would strongly recommend you to ask your Dr to put you back on 75 mcg.

Good luck
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2 Comments
My daughter’s end0I put her on levothyroxine after thyroid cancer. I requested her to be put on Synthroid because after my thyroid cancer I was put on the generic and didn’t like how it made me feel. I have been on Synthroid for years with good results. The doctor told me I was imagining it because the genetic and the name drug are the same. My body tells me otherwise.
They are not the same and you are right! The generic is not regulated from company to company so dosing amounts are not always the same because the pharmacy buys from whichever company is offering it the cheapest. However, Synthroid is highly regulated so you are getting the exact dose every time.
Avatar universal
Thank you everyone for your prompt responses.  I will def call my endo and have him put me back on levothyroxine.

anandbharti - He did up my dose from Levothyroxine 75mcg to Synthroid 88mcg.

TSH - 10 (Checked 2 months ago)
T3 and T4 - He did not tell me but said they were in the normal ranges.  
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Avatar universal
Sometimes people have a reaction to the fillers or buffers used in the tablets, this could be the case with you, you need to watch out for any swelling of the your throat or airway. I was on Levo for 6 months and it did nothing for me, but it did not cause any problems either, but when I was switched to Synthroid, it seemed I became really symptomatic also, every one I have talked to says it can't be the drug, and is Hypo symptoms, it seems odd that I started getting hit with all these symptoms right after starting Synthroid.
just like you. Wish I could help more but I never determined why it happened, when I mentioned it to my MD, he said the same thing "It can't be the Medication" Sure!
Good Luck FTB4
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Avatar universal
Look up the side effects on Drug.com. If they are listed or even if they're not, call him and tell him you want to go back to your old drug. If he says no and won't hear you out, it's time for a new specialist. Trust me, been there, had that happen too many times. What you don't want is a doctor who doesn't believe that you know your body better than he does.
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315318 tn?1353251800
I am sorry to read about your symptoms. Are you taking the same dose of the generic Levothyroxine as the sythroid dose ? From your symptoms it seems you may be taking a higher dose. Have you also changed the way you take your pill ? For example, In my own case , I use to leave a shorter gap between taking the pill and having my breakfast. When I increased the interval, I found that I slowly started losing weight, a probable indication of receiving a higher "effective dose" !!
I hope you feel better soon
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