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Synthroid-Cytomel-Cancer

I had a thyroidectomy due to cancer on May 23rd. Upon leaving the hospital I was put on Calcitriol 0.25mcg and Cytomel 25mcg. I felt better than I have in years until I had the RAI treatment. (I still had 3 small pieces of my thyroid left until then) I had to stop the Cytomel before the RAI but started back on it shortly afterward as well as starting Synthroid 150mcg. All meds are once daily. Shortly afterward the fatigue set in and the brain fog then my pulse rate started going up and I get dizzy. For example, yesterday I felt like I was going to faint while in the shower. I checked my blood pressure when I got  out  and it  was 100 / 60 and pulse was 118. My husband wanted me to go to the ER but I wouldn't. A couple hours later it was 99/ 60-pulse 100. Two hours later it was 110/68-pulse 84. Before the surgery my blood pressure was about always 120/80 and pulse was in the low 70's. I don't know if it makes a difference but I also take Benadryl three times a day for hives. My endro is out of town till the 30th. I know this is caused from the medications but I have no idea how they should be adjusted since I've only been taking them for a short times. I get an answering machine at the DRs. office but I don't think this is an emergency. I had blood work done last week but I have no idea what the results are. I'm scheduled to see the endo Aug. 13th. Any suggestions and is this more serious than I think.
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Avatar universal
It's worth it to check B-12, although I don't think that has anything to do with your current dilemma.

Have you tried splitting your Cytomel into two half doses?  Has that helped at all?
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Avatar universal
My B-12 hasn't been checked so I don't know.
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Avatar universal
T3 and T4 are the two main thyroid hormones.  T4 is all made in your thyroid and is the "storage" for of the thyroid hormones.  It basically floats around in your bloodstream until cells need thyroid hormone.  However, before cells can use it, T4 has to be converted to T3, which is the "active" form of the thyroid hormones, the only form your cells can use.  This conversion process happens in many sites throughout the body.  T3 is also what you are taking when taking Cytomel.  So, it's very important to know what T3 is doing.  When you are taking T3 meds (Cytomel), it's imperative.  If you're taking T3, and they're not measuring your FT3, it's a little like a diabetic taking insulin without measuring blood sugar levels.

I found this:

One USP unit or one IU of Vitamin D activity is equal to 0.025 mcg vitamin D (1 mg = 40,000 units).

So, as I do the math, 0.25 mcg Rocaltrol would be equivalent to 10 IU.  However, I also see that 0.25 -0.50 mcg is the dose that it comes in.  So, maybe I'm missing something.  I don't take D, so I'm no expert.

What's your B-12 level?
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Avatar universal
No she didn't test the FT3. What is that? She has me taking 0.25mcg of Rocaltrol. (vitamin D) I'm sure she's going to say it's low because I smoke and she's probably right. I do need to quit smoking anyway. My B-12 might be low also.
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Avatar universal
After thyroid cancer, they usually want to keep your TSH very low to lessen the possibility of regrowth and recurrence.

You do have to ask your doctor about supplementing D.  If D level isn't adequate, thyroid hormones can't get into cells and be metabolized properly.  With a deficiency like yours, people are often told by their doctors to supplement at something like 50,000 IU per week until levels start to come up.  Don't do that without consulting your doctor first.

They didn't test FT3?

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Avatar universal
I just called the lab and got a report on my blood work. My 25-OH Vit D is low at 22.
Calcium is normal at 9.7
TSH is low at 0.022
Free T4 is normal at 1.37
I really don't know what to do other than breaking the cytomel into 2 doses. Any suggestions? Thanks.
Helpful - 0
Avatar universal
I think I'll only take half a Cytomel for a few days and see what happens. My endo told me after you have thyroid cancer only an endo can change your meds. She said it didn't have to be her but it had to be an endo. She said if I ever had to go to the ER for anything don't let them change my meds.
This is still all new to me and I wasn't even aware that the Synthroid is T4 and the Cytomel is T3. I thank you for helping me understand better.
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Avatar universal
25 mcg of Cytomel is a lot to take at one time.  T3 is very fast acting, peaks about 3 hours after taking it, and deserts you a couple of hours after that.  To keep more even levels of FT3, most people split the Cytomel into two half dose, one first thing in the morning with their levo and the next late morning to early afternoon (depending on schedule).  This keeps FT3 more level throughout the day.

Synthroid is T4.  Our bodies must convert T4 to T3 before our cells can use it.  So, when you add T4 (Synthroid) to your meds, both FT3 and FT4 should rise.

Your Synthroid has had time to stabilize in your system since 6/16, so a retest is due.  Would your PCP order FT3, FT4 and TSH since your endo is away?

My guess is that once FT4 rose, your FT3 did as well, and now 25 mcg T3 is too much with the two drugs combined.  

If your PCP won't help, and this continues to happen, I'd want to have my FT3, FT4 and TSH test and evaluated.  The ER is an option.
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Avatar universal
I started Synthroid June 16. I take the Cytomel in one dose 4 hours after taking the Synthroid.
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Avatar universal
You are currently taking 150 mcg Synthroid and 25 mcg Cytomel?  How long ago did you start Synthroid?  Do you split your dose of Cytomel into two or more partial doses?
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