Tamoxifen
The Comprehensive Guide to Tamoxifen in Breast Cancer Treatment With Dr. Rahul Singh, Medical Oncologist, Medical Advisor, Learn Look Locate.



Tamoxifen: A Key Player in Breast Cancer Treatment
Tamoxifen, under the recognized brand names Nolvadex® and Soltamox®, is a pivotal drug classed as a selective estrogen receptor modulator (SERM). It’s renowned for its effectiveness in managing various stages of hormone receptor-positive breast cancer in both men and women.
Understanding Tamoxifen
Tamoxifen, available under the brand monikers Nolvadex® and Soltamox®, is a recognized selective estrogen receptor modulator (SERM). Its primary use is:
- Post-operative treatment to diminish the risk of hormone receptor-positive, early-stage breast cancer recurrence in both genders.
- Managing advanced-stage, hormone receptor-positive breast cancer.
- After surgery, it’s employed to decrease the risk of invasive breast cancer in those diagnosed with hormone receptor-positive DCIS (ductal carcinoma in situ).
- As a preventive measure for those with an elevated risk of breast cancer but without a diagnosis.
Notably, concurrent intake of Tamoxifen with aromatase inhibitors such as Arimidex (anastrozole) or Femara (letrozole) is discouraged.

How Does Tamoxifen Function?
Tamoxifen operates by hindering estrogen’s influence on hormone receptor-positive breast cancer cells. It achieves this by occupying the estrogen receptors on these cells, preventing estrogen from driving the growth and multiplication of these malignant cells. Notably, its efficacy is limited to hormone receptor-positive breast cancer.
Is Tamoxifen Suitable for Everyone?
Tamoxifen is predominantly prescribed for:
- - Early-stage or advanced-stage, hormone receptor-positive breast cancer in both pre- and post-menopausal women, as well as men.
- - Post-operative care for women diagnosed with hormone receptor-positive DCIS, reducing the risk of invasive breast cancer onset.
- - Those with an elevated risk of breast cancer but haven't received a diagnosis.
However, Tamoxifen might not be recommended for those:
- - With a history of blood clots or on anticoagulants due to increased clotting risks.
- - Who are pregnant, attempting to conceive, or breastfeeding due to potential embryonic harm. Non-hormonal birth control methods are advised during Tamoxifen treatment.
Survivor Testimonials

“The 8 years I was taking tamoxifen felt safe. It was only when I developed a thickened endometrial that I discovered the cause was tamoxifen. I still believe in the drug and would have preferred to have been able to stay on it. But after my issues, best to try something different.”
Christine Handy

“Being on tamoxifen has given me some peace knowing I have a line of defense working to help decrease my chance of recurrence.”
Jena
The Advantages of Tamoxifen
Tamoxifen has been a beacon of hope for countless individuals diagnosed with hormone receptor-positive breast cancer. Its benefits include:
- - Diminishing the risk of breast cancer recurrence by up to 50%.
- - Halving the risk of developing cancer in the opposite breast.
- - Ancillary health benefits, such as improved bone density post-menopause and cholesterol level reduction.

Duration and What to Anticipate with Tamoxifen
Tamoxifen is available both as a pill and liquid, catering to individual preferences. Typically, it’s taken daily, with consistency in timing being crucial. Duration varies based on diagnosis and individual factors, but it’s generally prescribed for five years post-surgery. Ongoing consultations with oncologists help determine the optimal treatment duration.
Potential Side Effects of Tamoxifen
While Tamoxifen has undoubted benefits, it’s not without its side effects. Common ones include:
- Hot flashes
- Mood fluctuations
- Fatigue
- Nausea
However, some rare but severe side effects necessitate immediate medical attention, including:
- Signs of endometrial cancer
- Blood clot symptoms
- Stroke indications
- Cataract development
- Liver complications
Regular communication with healthcare providers can ensure effective side effect management and timely interventions.
Medications to Sidestep While on Tamoxifen
Certain medications can diminish Tamoxifen’s effectiveness. It’s crucial to consult healthcare providers regarding any potential drug interactions, especially with strong or moderate CYP2D6 inhibitors, many of which include specific antidepressants.
Affording Tamoxifen
Tamoxifen’s long-standing generic availability means there are no dedicated pharmaceutical support programs. However, for those prescribed the liquid form, Soltamox, there may be prescription card eligibility. Patients facing financial constraints are advised to explore local programs or consult their care team for assistance.
FAQs
1. What Are The Main Side Effects Of Tamoxifen?
The main Side effects are joint pains, hot flashes, and weakening of the bones.
2. How do you mitigate the cardiovascular effects of AI as well as the osteoporosis and joint issues due to no estrogen? At what point will the oncology world address the increased cardiovascular issues associated with these drugs?
It is important to understand everyone’s risk of cardiac disease and risk factors. While AIs are associated with an increased risk of cardiovascular disease relative to tamoxifen (may have a bit of risk reduction), they may have a similar risk relative to a placebo.
3. Is There Only A One-Size-Fits-All All Approach To The Dosage Of These Meds? I Could Not Tolerate Anastrozole (Did Not Sleep For 4 Months) So My Oncologist Switched Me To Tamoxifen Even Though I’m Postmenopausal. I’m Starting On A Lower Dose. Are The Dosages Connected To Cancer Type And Stage At All?? Joint Pain Is The Worst With A Lack Of Estrogen. I’m Taking Veozah Which Helps With Hot Flashes And Night Sweats.
As far as we know, there are only fixed doses for AIs. As far as Tamoxifen, lower doses such as 5 or 10 mg have been studied in non-cancer types such as ADH, DCIS, and LCIS with better tolerance.
4. Why do AI's cause arthralgia and will that pain ever truly go away?
5. Are there fertility side effects, and if the ovaries or period can return after stopping taking it?
6. The potential long-term side effects of these drugs including things infertility, and neuralgia. Then I learned how to effectively manage side effects like joint pain, hot flushes, and blurry vision (these are some I had).
7. Will hot flashes improve over time? If not what can I do to make them less intense?
They should improve, talk to your doctor about Venflaxine or Veozah.
8. How to deal with the side effects of the combination of AI and Zoladex.
9. I've been on Tamoxifen for almost 5 years and my hair is thinner than ever. Can I take supplements to strengthen it?
10. Is there anything close to being developed as an alternative to Tamoxifen?
11. Why has there not been anything else with millions of dollars in research to help us and cause fewer side effects other than the food that we have?
12. Is it safe to take a break from the AI in order to try and conceive?
13. If they got all the cancer out and had radiation /chemo, why do you need to take these additional drugs?
14. I’m HER2+ so no meds for me just immunotherapy after chemo, radiation and 4 surgeries. Fear it will return. Thoughts?
15. Is there any alternative to tamoxifen/AIs?
16. How can tamoxifen users stay on top of uterine cancer risks? Best screening and how often?
17. Interested in learning about osteoporosis and Aromatase Inhibitors/Tamoxifen. The doctor has me on tamoxifen since I have osteoporosis. I’m post-menopausal, how often should I have a Dexa scan and how do osteoporosis drugs affect AI or Tamoxifen?
18. Letrozole (Femara); awful foot (heal) pain. What’s the best way to get through this? On this for 5 yrs and only 4 months into it.
First would recommend talking to your primary oncologist about taking a break or switching to another AI such as Anastrozole.
19. I’ve been on Arimidex since March 2023 body aches I feel are getting worse what can I do or take?
20. I’d like to know how can us ladies protect our skin hair heart bones etc. while on meds like letrozole?
21. After an infusion of Reclast, I got the jawbone side effect- I feel like I need to go off Arimidex
22. I already had full-blown osteoporosis when my breast cancer was found and was taking Fosamax. Now that I’ve been taking Arimidex my bones have even worsened.
23. Mayo said 10-15% chance of reoccurrence if I take tamoxifen it drops by half. so, 2-7%. I'm not thinking it’s worth it. Are these numbers correct?
24. Some articles say 7% chance of cancer not coming back if you take hormone blockers but some articles say 50% better odds.. what is correct?. so, 2-7%. I'm not thinking it’s worth it. Are these numbers correct?
25. Do magnesium supplements help? My oncologist said I had a 2.7% 'gain' in life expectancy. Online I read about 45% chance of cancer not recurring.
26. What is the best hormone therapy if you are 3x positive and post-menopausal? so many options!
27. Do the side effects reach a certain peak? I seem to have more joint and muscle aches and weakness, 6 months in.
28. The US may be different but are you offered a hormone test before going on inhibitors? After menopause, we should know where the estrogen is coming from.
Only FSH/Estradiol levels are checked if we believe the person may be in menopause.
29. Adrenal glands, fat cells, testosterone all these convert to estrogen so do inhibitors stop this happening or get rid of estrogen?
It depends on the menopausal state, as they change and Tamoxifen and AIs work differently. The latter can only be used in women who are post-menopausal.
30. When they take you off Tamoxifen after 5 years, how is your body then protected from blocking Estrogen?
It isn’t technically protected, but depending on what your previous Breast pathology was, it may not require further extension of therapy as the risk for relapse isn’t greater.
31. How can we prevent osteoporosis and osteopenia from these drugs?
Calcium and Vitamin D ingestion and weight-bearing exercises.
32. How do Aromatase Inhibitors work differently?
Although they are all the same “class” of drugs, meaning they have Letrozole and Anastrozole have small conformation changes that can lead to different side effects/tolerances for people. Exemestane works slightly differently and as such has a slightly different side effect profile compared to Anastrozole/Letrozole.
33. Do most oncologists check hormone levels of people being out into medical menopause so they can take an AI?
In-Depth Discussion: Tamoxifen and Aromatase Inhibitors
Gain valuable insights from Dr. Rahul Singh’s comprehensive interview, where he delves into the intricacies of Tamoxifen and Aromatase Inhibitors in breast cancer treatment. This engaging video offers a deep understanding of these crucial medications, their roles in hormone receptor-positive breast cancer management, and their impact on patient care.
Doctor's Perspective

Rahul Singh, MD
Medical Oncologist & Hematologist, Medical Advisor, Learn Look Locate
“Breast cancer is a difficult diagnosis and understanding what may drive it will empower you. Learn Look Locate is here to bridge that gap and deliver accurate information that is easily understandable.”
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