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:

However, Tamoxifen might not be recommended for those:

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

Stage 2, Florida

“Being on tamoxifen has given me some peace knowing I have a line of defense working to help decrease my chance of recurrence.”


Stage 3, Illionois

The Advantages of Tamoxifen

Tamoxifen has been a beacon of hope for countless individuals diagnosed with hormone receptor-positive breast cancer. Its benefits include:

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.


Explore our comprehensive FAQ section where Dr. Rahul Singh, a renowned Medical Oncologist and Medical Advisor at Learn Look Locate, directly addresses personal questions from breast cancer survivors about Tamoxifen. Gain valuable insights and expert advice tailored to your journey.

What Are The Main Side Effects Of Tamoxifen?

The main Side effects are joint pains, hot flashes, and weakening of the bones.

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.

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.

Why do AI's cause arthralgia and will that pain ever truly go away?

Risk factors for arthralgias have not been fully understood, but the decrease in estrogen levels with aromatase inhibition may play a role. After discontinuation, the pain should resolve.

Are there fertility side effects, and if the ovaries or period can return after stopping taking it?

There are no long-term side effects on fertility, and they all should return after discontinuation. If not, recommend close follow-up with GYN.

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).

Ideally should not have long-term side effects after discontinuation. If symptoms linger, would recommend further work-up for other reasons/causes.

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.

How to deal with the side effects of the combination of AI and Zoladex.

Depends on the specific side effects.

I've been on Tamoxifen for almost 5 years and my hair is thinner than ever. Can I take supplements to strengthen it?

This can be improved with topical minoxidil in the majority of cases.

Is there anything close to being developed as an alternative to Tamoxifen?

Not at this time.

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?

Hard to answer this question. These are well-proven drugs that are effective in reducing the risk of recurrence of cancer and an alternative to chemotherapy in a lot of situations.

Is it safe to take a break from the AI in order to try and conceive?

Depending on your tumor and risk factors for recurrence, this would be an important conversation with your oncologist. It some situations it is.

If they got all the cancer out and had radiation /chemo, why do you need to take these additional drugs?

Because tumors that profile as endocrine positive (Estrogen/Progesterone Positive) have a driving factor that if not suppressed can cause cancer cells to come back.

I’m HER2+ so no meds for me just immunotherapy after chemo, radiation and 4 surgeries. Fear it will return. Thoughts?

If HER2 positive (unclear your tumor profile), would discuss combination blockade of Her-2 receptor with Herceptin/Perjeta. Afterward, at this point unfortunately we have no further therapy, but in the same light risk of relapse is much less.

Is there any alternative to tamoxifen/AIs?

Not at this time.

How can tamoxifen users stay on top of uterine cancer risks? Best screening and how often?

Recommend close follow-up with GYN, and any abnormal uterine bleeding should be identified and evaluated by GYN.

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?

Tamoxifen isn’t associated with Osteoporosis as AIs are. Usually, a patient should receive a DEXA scan every 2 years.

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

I’ve been on Arimidex since March 2023 body aches I feel are getting worse what can I do or take?

Can try NSAIDs, exercising, Acupuncture, Duloxetine, or switch of AI.

I’d like to know how can us ladies protect our skin hair heart bones etc. while on meds like letrozole?

Many possible side effects, its important to stay on top of your scheduled Bone Density Scans, annual physicals (check cholesterol panel), etc.

After an infusion of Reclast, I got the jawbone side effect- I feel like I need to go off Arimidex

Discuss with your primary Oncologist about Osteonecrosis of the Jaw which is a serious side effect associated with Bisphosphonates and requires a Dentist evaluation.

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.

Talk to your oncologist about other treatments for osteoporosis such as Prolia.

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?

This is a discussion to have with your oncologist and the risk assessment of side effects with the medication, which you may or may not be experiencing.

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?

This is difficult to answer as the risk of recurrence is individualized to every patient and varies.

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.

I’m not aware of any specific research studies (Randomized controlled studies) proving Magnesium Supplements decrease the risk of recurrence of breast cancer. They may help symptomatically from muscle aches associated with AIs, but not been proven by clinical studies.

What is the best hormone therapy if you are 3x positive and post-menopausal? so many options!

It was initially thought that AIs were superior to Tamoxifen in breast recurrence, but the data is based on low-quality data. The belief is there are fewer side effects with AIs compared to Tamoxifen and initially the preference for many oncologists.

Do the side effects reach a certain peak? I seem to have more joint and muscle aches and weakness, 6 months in.

There is no specific peak time for side effects. Can occur at any time.

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.

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.

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.

How can we prevent osteoporosis and osteopenia from these drugs?

Calcium and Vitamin D ingestion and weight-bearing exercises.

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.

Do most oncologists check hormone levels of people being out into medical menopause so they can take an AI?

FSH and serum estradiol levels to assess if they are in the postmenopausal range.

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.

Play Video

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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