[Anonymous]

#1038660

Evening Sam,
The answer to this question about why one drug(Tapazole) might be prescribed over another(PTU)can be for different reasons. The main reason seems to be doctor preference. However, due to the fact that a substantial number of people experience allergies to Tapazole, I would think this may be the reason for the doctors to lean towards PTU.
You might want to ask your doctor what his/her thinking is on this issue.

Best Wishes,
Jan
Online Facilitator, NGDF

[Anonymous]

#1125925

I believe that the difference between PTU and Tapazole is that one of them prevents the thyroid from absorbing iodine, while the other one prevents the absorbed iodine from being synthesized into thyroid hormone. The net effect is basically the same — both drugs result in lower production of thyroid hormone.

The reason my doctor gave me for prescribing Tapazole rather than PTU is that Tapazole is stronger, so you don’t need to take as many pills, as often.

[Anonymous]

#1125926

I will soon be going on either PTU or Tapazole. I am wondering if anyone knows the difference between the two and why one is prescribed over another? PTU seems to be quite a bit cheaper through my insurance company so I want to find out as much as possible before going on the meds in case I have a choice. Maybe I won’t get a choice but just wanting to prepare myself. Also, I have been experiencing a lot of blurriness when I try to focus my eyes. Does anyone know if that is a symptom of TED or what the symptoms are? Thanks for your input.
JennD

[Anonymous]

#1125927

What I know about the issue is that while different chemicals, PTU and Tapazole do essentially the same thing, i.e. they block the production of thyroid hormone by introducing a chemical into the process which interferes with the biochemical reaction that takes place to turn iodine into thyroid hormone. The thyroid produces mostly T4, which must be converted into T3 elsewhere in the body — the PTU can also interfere with this process, while the Tapazole apparently does not. So individuals whose bloodwork suggests wildly out-of-line T3 levels may be considered more seriously for PTU.

PTU comes in only one dose — I think it is 50 mg, but it’s been a long time…. — and it has a very short biological life in the body, so we typically take several pills, several times a day. And it is important to try to make the timing in between doses reasonably consistent. Tapazole is usually (but not always) one dose a day. I have heard more people relate that they are taking multiple doses of Tapazole lately, so it sounds as if doctors are doubling up more than they did when I was first diagnosed seven years ago.

Also, in women of childbearing age, PTU is often used because it is safer for the fetus if the woman becomes pregnant. Both PTU and Tapazole are Class D drugs which are known to cross the placenta and could harm the baby. But PTU is thought to cross less, and also (because of the multiple pills, multiple times a day) it may be easier to adjust the dose of PTU down to a level which is safer for the baby. I’m not sure of that last part, though.

I hope this helps,
Bobbi — NGDF Online Facilitator

[Anonymous]

#1125928

Thank you for the information. I have to retake my iodine uptake test today and tomorrow, which will determine whether I have RAI or go on med’s. I am hoping to understand as much as possible so that when my dr. tells me what treatment is best, I will be educated/informed.

[Anonymous]

#1125929

I believe that PTU limits your thyroid’s ability to absorb iodine, while with Tapazole, your thyroid will absorb iodine, but will be limited in its ability to convert it into thyroid hormone. The end result is essentially the same. I was on Tapazole and had good results (going on 5 years of remission).

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