Anastrozole's effect on TSH Thyroid level ???

Posted by katrina123 @katrina123, Jul 19 11:20am

I had my thyroid removed almost 5o years ago and my TSH levels have ranged from .550 mU/l to a high of 1.350 mU/l . Several weeks after I started taking the Anastrozole my TSH level was 2.97 mU/l which is more than twice the highest thyroid level I have had. My dosage has never changed. I can’t help but wonder if the estrogen lowering drug has also raised my TSH level. I was just wondering if this has happened to any of you. Thanks Katrina123

Hi @katrina123, the FDA product monograph states (page 7) https://www.accessdata.fda.gov/drugsatfda_docs/label/2005/020541s016lbl.pdf

"In multiple daily dosing trials with 5 and 10 mg, thyroid stimulating hormone (TSH) was measured; there was no increase in TSH during the administration of ARIMIDEX (anastrozole). ARIMIDEX does not possess direct progestogenic, androgenic, or estrogenic activity in animals, but does perturb the circulating levels of progesterone, androgens, and estrogens."

I'm tagging fellow members @dorisena @shelleyc @kathyomaha55 and @remi, who have experience with breast cancer and thryoid issues.

Katrina, as you know, everyone is different, and I would talk to your oncologist and pharmacist about possible drug interactions and what adjustments might have to be made for you. Are you taking Synthroid (levothyroxine) since having your thyroid removed?

Liked by kathyomaha55

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@colleenyoung

Hi @katrina123, the FDA product monograph states (page 7) https://www.accessdata.fda.gov/drugsatfda_docs/label/2005/020541s016lbl.pdf

"In multiple daily dosing trials with 5 and 10 mg, thyroid stimulating hormone (TSH) was measured; there was no increase in TSH during the administration of ARIMIDEX (anastrozole). ARIMIDEX does not possess direct progestogenic, androgenic, or estrogenic activity in animals, but does perturb the circulating levels of progesterone, androgens, and estrogens."

I'm tagging fellow members @dorisena @shelleyc @kathyomaha55 and @remi, who have experience with breast cancer and thryoid issues.

Katrina, as you know, everyone is different, and I would talk to your oncologist and pharmacist about possible drug interactions and what adjustments might have to be made for you. Are you taking Synthroid (levothyroxine) since having your thyroid removed?

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I have not had my thyroid removed. But I was taking levothyroxine for over 5 years before I had IDC. I took anastrozole for 12 months then switched to exemestane last November, neither drug effected my thyroid levels. I currently take 88 mcg daily for my thyroid. I have it tested yearly. Good luck and yes discuss it with both doctors. In 2016 I had trouble getting my dosage right, they had to increase it – but you have to take the new dose for 90 days before they know if it worked at that dosage. They changed my dosage 3 times that year. It was frustrating. Long before I had BC – so it may be completely unrelated.

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@katrina123 Hi, Katrina… I'm going to take a shot in the dark here. I know that some of us worry about taking anastrozole and suffering from hair thinning, and then start taking Biotin in large doses hoping to counteract that. Biotin does help… it also leads to falsely high thyroid test levels. Many of us know to go off Biotin a few days before a thyroid test. By any chance are you supplementing with Biotin?

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Hi, I can’t answer because I don’t take synthroid (levothroxine) or anastrozole, I don’t have a thyroid but all of the synthetic meds they tried on me I had reactions so I’m taking GTA Forte II for thyroid and numbers have been great for a few years now.
They didn’t even try starting me on anastrozole until I had breast cancer, as I said tried I’m not taking anything because as it turned out I’m allergic to something in that med. they tried one other and same thing.

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I was on Anastrozole for over a month and had stomach problems so switched to exemestane and have been taking this for one month. No stomach issues so far, but at my yearly physical my TSH was low. Was taking synthroid for 30 years at 88mcg. My primary care physician changed the dosage to 75mcg and will retest blood and see me in two months.

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@colleenyoung

Hi @katrina123, the FDA product monograph states (page 7) https://www.accessdata.fda.gov/drugsatfda_docs/label/2005/020541s016lbl.pdf

"In multiple daily dosing trials with 5 and 10 mg, thyroid stimulating hormone (TSH) was measured; there was no increase in TSH during the administration of ARIMIDEX (anastrozole). ARIMIDEX does not possess direct progestogenic, androgenic, or estrogenic activity in animals, but does perturb the circulating levels of progesterone, androgens, and estrogens."

I'm tagging fellow members @dorisena @shelleyc @kathyomaha55 and @remi, who have experience with breast cancer and thryoid issues.

Katrina, as you know, everyone is different, and I would talk to your oncologist and pharmacist about possible drug interactions and what adjustments might have to be made for you. Are you taking Synthroid (levothyroxine) since having your thyroid removed?

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Thank you for the information. I will add this question to my list for my next oncology visit.

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@kathyomaha55

I have not had my thyroid removed. But I was taking levothyroxine for over 5 years before I had IDC. I took anastrozole for 12 months then switched to exemestane last November, neither drug effected my thyroid levels. I currently take 88 mcg daily for my thyroid. I have it tested yearly. Good luck and yes discuss it with both doctors. In 2016 I had trouble getting my dosage right, they had to increase it – but you have to take the new dose for 90 days before they know if it worked at that dosage. They changed my dosage 3 times that year. It was frustrating. Long before I had BC – so it may be completely unrelated.

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Good to know. Thanks

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@pattycincinnati

I was on Anastrozole for over a month and had stomach problems so switched to exemestane and have been taking this for one month. No stomach issues so far, but at my yearly physical my TSH was low. Was taking synthroid for 30 years at 88mcg. My primary care physician changed the dosage to 75mcg and will retest blood and see me in two months.

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Did your doctor give you any explanation for the change?

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@colleenyoung

Hi @katrina123, the FDA product monograph states (page 7) https://www.accessdata.fda.gov/drugsatfda_docs/label/2005/020541s016lbl.pdf

"In multiple daily dosing trials with 5 and 10 mg, thyroid stimulating hormone (TSH) was measured; there was no increase in TSH during the administration of ARIMIDEX (anastrozole). ARIMIDEX does not possess direct progestogenic, androgenic, or estrogenic activity in animals, but does perturb the circulating levels of progesterone, androgens, and estrogens."

I'm tagging fellow members @dorisena @shelleyc @kathyomaha55 and @remi, who have experience with breast cancer and thryoid issues.

Katrina, as you know, everyone is different, and I would talk to your oncologist and pharmacist about possible drug interactions and what adjustments might have to be made for you. Are you taking Synthroid (levothyroxine) since having your thyroid removed?

Jump to this post

Yes I have taken the same amount of thyroid medication for almost 50 years.

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@katrina123

Did your doctor give you any explanation for the change?

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No she didn't. I hope the lower dose straightens it out. I have been through chemotherapy, radiation, and now infusions of herceptin along with the exemestane so there could be several reasons!

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@remi

Hi, I can’t answer because I don’t take synthroid (levothroxine) or anastrozole, I don’t have a thyroid but all of the synthetic meds they tried on me I had reactions so I’m taking GTA Forte II for thyroid and numbers have been great for a few years now.
They didn’t even try starting me on anastrozole until I had breast cancer, as I said tried I’m not taking anything because as it turned out I’m allergic to something in that med. they tried one other and same thing.

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Hello @remi,
As it has been a while since you last posted I was wondering how you are doing I hope you are feeling good and enjoying the beginning of fall.
Have you had any follow-up diagnostic tests recently?

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Hi, Teresa….I’m doing pretty good. I’m taking a natural thyroid replacement GTA Forte ll the va endo had my labs ran numbers were good and not that I don’t totally trust them I went to my primary care here where I live also and asked her to have my labs drawn. They were good too. 🤗
In June the oncologist canceled my labs and appointment with her until they open back up and can also get a ct of my throat, breast, lungs, liver and kidneys. They finally called and scheduled that for the end of this month, the same day I’ll have my oncology labs drawn. Then she will call me for an appointment or get in my face appointment on the computer 🤣. Hope everyone is well and staying safe.
I’m here if anyone needs to chat or has questions, take care and God Bless

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@remi

Hi, Teresa….I’m doing pretty good. I’m taking a natural thyroid replacement GTA Forte ll the va endo had my labs ran numbers were good and not that I don’t totally trust them I went to my primary care here where I live also and asked her to have my labs drawn. They were good too. 🤗
In June the oncologist canceled my labs and appointment with her until they open back up and can also get a ct of my throat, breast, lungs, liver and kidneys. They finally called and scheduled that for the end of this month, the same day I’ll have my oncology labs drawn. Then she will call me for an appointment or get in my face appointment on the computer 🤣. Hope everyone is well and staying safe.
I’m here if anyone needs to chat or has questions, take care and God Bless

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Hi @remi,

I appreciate the update! I'm glad to hear that your lab numbers are good. I look forward to hearing from you again. I hope your oncology tests turn out good as well. If you are comfortable doing so, will you post again after those tests?

Stay safe and be well!

Liked by sparklegram

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@elizm

@katrina123 Hi, Katrina… I'm going to take a shot in the dark here. I know that some of us worry about taking anastrozole and suffering from hair thinning, and then start taking Biotin in large doses hoping to counteract that. Biotin does help… it also leads to falsely high thyroid test levels. Many of us know to go off Biotin a few days before a thyroid test. By any chance are you supplementing with Biotin?

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I can confirm that biotin will affect thyroid tests. I take it due to thinning hair and poor nail quality and I don't actually think it's helped my hair or nails at all (ha ha) but it did increase my TSH level in a recent blood test by a few points. My doctor didn't request I quit taking it for a few days and it caused some confusion, so ………..yes, quit taking Biotin for a few days before a blood draw for TSH.

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@elizm

@katrina123 Hi, Katrina… I'm going to take a shot in the dark here. I know that some of us worry about taking anastrozole and suffering from hair thinning, and then start taking Biotin in large doses hoping to counteract that. Biotin does help… it also leads to falsely high thyroid test levels. Many of us know to go off Biotin a few days before a thyroid test. By any chance are you supplementing with Biotin?

Jump to this post

Biotin can mess up thyroid tests in unexpected ways… it can make the results read extreme at either end of the “normal” range. It happened to me. I didn’t know about that possibility before my thyroid test went askew, but I then researched possible causes and figured it out. My PCP was ready to start taking more drastic measures to address my “thyroid problem”— but she never asked about biotin. I brought it to her attention after my research. Subsequent testing after I quit the biotin has been normal. My hair was starting to be “okay” after chemo, but then the anastrozole thinned it greatly. (I was taking Biotin to try to thicken it.) I have been on anastrozole for four years.

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