Aa
Anyone know the math for switching from synthetic to a desiccated med?
I am coming off 88 mcg of levothyroxine and being placed on 37.5 Nature Thyroid. I'm not sure what the transition/conversion should be. Can anyone tell me does this seem right?
Thank you again... Just looking for some reassurance with this new med and doctor.
Thank you again... Just looking for some reassurance with this new med and doctor.
Best Answer
The "conversion chart" says that 100 mcg levo is roughly equivalent to 65 mg desiccated, so 32.5 mg would be roughly equivalent to 50 mcg. However, bear in mind that the two are not really equivalent since T3 and T4 are very different. The chart only offers a place to start, and your starting dose should take that into account along with other factors, like your typical drug tolerance and the fact that T3 sometimes takes a little getting used to. So, your overall dose will be a little on the low side, but I don't think it's an unreasonable place to start.
There are a number of conversion tables. This is one of those.
http://centraldrugsrx.com/pdf/Thyroid_Conversion_Chart_08-13a.pdf
If you look at the table you will note that 100 mcg of synthetic T4 is supposed to be the equivalent of one grain (60 mg) of Armour Thyroid. Then you look further and it shows 100 mcg of T4 to be equivalent to 25 mcg of T3. This means that each mcg of T3 is equal to 4 mcg of T4. Since Armour Thyroid contains 39 mcg of T4 and 9 mcg of T3, if you convert the T3 to equivalent T4 (multiply by 4), then 39 plus (9 times 4) equals only 75, not the 100 shown in the table.
This suggests that the conversion of 100 mcg of T4 equals 60 mg of Armour is wrong. By the above calculation the 60 mg of Armour would only be equal to 75 mcg of T4. In addition there is a scientific study that attempted to quantify the relative effects of T4 and T3. They came to the conclusion that the factor used to convert T3 to equivalent T4 should be 3.3, not 4. Taking that into consideration, one grain of Armour would only be equal to about 70 mcg of T4.
From that aspect your new dosage is considerably lower than prior on T4 only. The 88 mcg dosage would be approx. equal to more than a full grain, or approx. 68 mg of Armour, which is considerably more than the new dose prescribed for you. So goolarra is correct that your new dose is low. Just be aware of how much of a reduction the new dose represents and the likelihood of degradation in your symptoms. Which leads me to the question: what is the cause for the change in meds? If it was because of you still having hypo symptoms, then I see little risk in switching to a full grain of Armour, but do it in two stages. That way you should have the best of both possible outcomes.
http://centraldrugsrx.com/pdf/Thyroid_Conversion_Chart_08-13a.pdf
If you look at the table you will note that 100 mcg of synthetic T4 is supposed to be the equivalent of one grain (60 mg) of Armour Thyroid. Then you look further and it shows 100 mcg of T4 to be equivalent to 25 mcg of T3. This means that each mcg of T3 is equal to 4 mcg of T4. Since Armour Thyroid contains 39 mcg of T4 and 9 mcg of T3, if you convert the T3 to equivalent T4 (multiply by 4), then 39 plus (9 times 4) equals only 75, not the 100 shown in the table.
This suggests that the conversion of 100 mcg of T4 equals 60 mg of Armour is wrong. By the above calculation the 60 mg of Armour would only be equal to 75 mcg of T4. In addition there is a scientific study that attempted to quantify the relative effects of T4 and T3. They came to the conclusion that the factor used to convert T3 to equivalent T4 should be 3.3, not 4. Taking that into consideration, one grain of Armour would only be equal to about 70 mcg of T4.
From that aspect your new dosage is considerably lower than prior on T4 only. The 88 mcg dosage would be approx. equal to more than a full grain, or approx. 68 mg of Armour, which is considerably more than the new dose prescribed for you. So goolarra is correct that your new dose is low. Just be aware of how much of a reduction the new dose represents and the likelihood of degradation in your symptoms. Which leads me to the question: what is the cause for the change in meds? If it was because of you still having hypo symptoms, then I see little risk in switching to a full grain of Armour, but do it in two stages. That way you should have the best of both possible outcomes.
Thanks Goolarra! Doc said starting a bit low to begin... he didn't want to shock my body with this new type of med. Looks like he's on track!
Is this conversion chart online here somewhere? Thxs bunches!
Is this conversion chart online here somewhere? Thxs bunches!
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