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Topic: Low Blood Sugar from Tamoxifen?

Forum: Managing Side Effects of Breast Cancer and Its Treatment —

This is a place to discuss concerns, tips and strategies for all types of side effects from all types of medications and treatments, (chemo/rads/hormonal/targeted/pain meds/etc.

Posted on: Nov 12, 2019 10:00PM

Veeder14 wrote:


I had another PET/CT scan today and when my blood sugar was checked it was 63. About 14 hours without food. It's usually between 85-100 before the scans. I've been on Tamoxifen for almost 9 months now and I'm wondering if it can cause low blood sugar. I really didn't have any symptoms but of course was hungry.

Dx 1/2/2018, ILC, Left, <1cm, Stage IB, Grade 1, 0/7 nodes, ER+/PR+, HER2- Surgery 1/25/2018 Lumpectomy: Left; Lymph node removal: Sentinel Radiation Therapy 3/7/2018 Hormonal Therapy 2/28/2019 Hormonal Therapy
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Nov 12, 2019 11:30PM - edited Nov 12, 2019 11:35PM by AliceBastable

You hadn't eaten, of course it was down. I'm mildly diabetic and had to go on a strict zero carb diet the day before a PET scan to get down below 100. We're you told not to eat anything? My instruction sheet said only diabetics had to alter their eating, and only for one day. Were you told not to eat for some reason?

And can I ask why you're having what sounds like frequent PET scans? Mine was because of a different cancer, not related to the breast one. My MO only orders scans of the patient has specific symptoms or really wonky bloodwork.

Endometrial cancer 2010, basal cell multiples, breast cancer 2018, kidney cancer 2018. Cancer's a bitch, but I'm a bigger one with more practice. Dx 5/2018, ILC/IDC, Left, 2cm, Stage IA, Grade 2, 1/1 nodes, ER+/PR+, HER2- Surgery 7/10/2018 Lumpectomy: Left; Lymph node removal: Sentinel Surgery 8/7/2018 Radiation Therapy 10/28/2018 Whole-breast: Breast, Lymph nodes
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Nov 12, 2019 11:59PM Veeder14 wrote:

Hi AliceBastable,

I've been having frequent PET scans for the last 3 years due to Melanoma not breast cancer. The instructions I was given each time was not to eat for at least 6 hours prior to the scan time. Could drink as much water as I wanted prior. Due to the time of my scan I would have had to get up and eat breakfast at about 5 am if I was going to eat an early breakfast. Decided to sleep instead since the Tamoxifen messes with my sleep so much. I guess I was just kind of shocked at having such a low blood sugar reading. Thank you for responding.

Dx 1/2/2018, ILC, Left, <1cm, Stage IB, Grade 1, 0/7 nodes, ER+/PR+, HER2- Surgery 1/25/2018 Lumpectomy: Left; Lymph node removal: Sentinel Radiation Therapy 3/7/2018 Hormonal Therapy 2/28/2019 Hormonal Therapy
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Nov 13, 2019 02:19PM gb2115 wrote:

A glucose level of 63 with fasting for 14 hours in a non-diabetic is fine. Your body will recognize and adjust by having your liver dump glycogen stores into the blood to compensate. They just drew your blood before that happened. I deal with lab work at work, and we ignore the non-diabetic glucose levels if they are a little low.

Dx IDC in October 2016, stage 2A, 1.2 cm ER/PR+ Her2-, Grade 2, 1/3 nodes. Mammaprint low risk luminal A, Lumpectomy + radiation + tamoxifen. Age 38 at diagnosis.
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Nov 13, 2019 02:44PM Veeder14 wrote:

Thanks so much gb2115 for writing back to me. I'll stop worrying about this now.

Dx 1/2/2018, ILC, Left, <1cm, Stage IB, Grade 1, 0/7 nodes, ER+/PR+, HER2- Surgery 1/25/2018 Lumpectomy: Left; Lymph node removal: Sentinel Radiation Therapy 3/7/2018 Hormonal Therapy 2/28/2019 Hormonal Therapy
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Nov 13, 2019 03:11PM AliceBastable wrote:

Maybe have a late-night healthy snack the evening before so your body hasn't gone without food so long?

Endometrial cancer 2010, basal cell multiples, breast cancer 2018, kidney cancer 2018. Cancer's a bitch, but I'm a bigger one with more practice. Dx 5/2018, ILC/IDC, Left, 2cm, Stage IA, Grade 2, 1/1 nodes, ER+/PR+, HER2- Surgery 7/10/2018 Lumpectomy: Left; Lymph node removal: Sentinel Surgery 8/7/2018 Radiation Therapy 10/28/2018 Whole-breast: Breast, Lymph nodes
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Nov 13, 2019 04:44PM ksusan wrote:

I have diabetes and tamoxifen seems to make my FBS go up.

Mutant uprising quashed. Dx 1/2015, IDC, Right, Stage IIA, 1/1 nodes, ER+/PR+, HER2- Dx 1/2015, DCIS, Left, Stage 0, Grade 3, 0/2 nodes Hormonal Therapy Tamoxifen pills (Nolvadex, Apo-Tamox, Tamofen, Tamone) Surgery Lymph node removal: Sentinel; Mastectomy: Left, Right Radiation Therapy Whole-breast Chemotherapy Cytoxan (cyclophosphamide), Taxotere (docetaxel)
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Nov 13, 2019 06:11PM Veeder14 wrote:

Hi Alice Bastable,

Yes, good idea. I did have some fruit at 10 pm. The hospital I go to reserves the morning PET scans for diabetic patients, so I'm always in the afternoon.

Hi Ksusan,

Sorry to hear it raises your blood sugar. I hope it's only minimally. Let's hope the side effects of Tamoxifen are reversed when done taking it.


Dx 1/2/2018, ILC, Left, <1cm, Stage IB, Grade 1, 0/7 nodes, ER+/PR+, HER2- Surgery 1/25/2018 Lumpectomy: Left; Lymph node removal: Sentinel Radiation Therapy 3/7/2018 Hormonal Therapy 2/28/2019 Hormonal Therapy

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