tamoxifen and thyroxine

[haggisplant]

if you started tamoxifen, how much did thyroid bloods/ dose need to change?

I know tamoxifen causes fatigue and foggineess but also wondering if it’s thyroid too as I know it can interfere with things. I do have a blood tests in a couple of weeks.

[Jaydee1507 Administrator]

I'm afraid that I don't have the specific answer to your question but can recommend that you get your thyroid levels checked if you are concerned.

Its also essential to check on key vitamins ferritin, folate, B12 & D3 as our thyroid hormone will not work well if these levels are less than optimal.

[Delgor]

haggisplant- I don't have the specific answer to your question either as I was only on Tamoxifen for a couple of months before I started taking thyroid medication and stayed on it for the recommended 5 years. My only gripe was that nobody had warned me that it would cause me to have a menopause overnight which came as a bit of a shock and neither was I told that I shouldn't have blood taken nor have a vaccination in the arm from which lymph glands were removed (only found this out from a forum member in recent times). 😒

[Bearo]

Sorry I can’t answer your question. I took Tamoxifen for five years (yes, menopause happened as soon as I started taking it) and when I completed the five years I discovered vit d was very low, B12 lowish and thyroid was borderline hypo, possibly central thyroidism.

I always wondered if breast cancer or Tamoxifen contributed to the low vits and the hypo dx, or if it was the other way round , or if they’re completely unrelated.

[Lulu2red]

There is definitely a connection between Tamoxifen & thyroid dysfunction. My mother was on Tamoxifen double dosage for 5 years. She became hypothyroid and was on Levothyroxine for the rest of her life. Unfortunately she also needed a hysterectomy when they found a mass. Thankfully it was benign but was told it was a side effect of the Tamoxifen. She survived it all and passed away at 89 years. Her breast cancer never returned. Tamoxifen is a dirty drug but it saves lives. The only regret she had was refusing breast reconstruction.

[haggisplant]

Returning ti say that yes, it had affected it at 6 weeks slightly, tsh 2.32 so I upped it by 25 every other day. Felt much better in a couple of weeks (in time for radiotherapy!)