Tamoxifen Gel (30 mL)
With both estrogenic and antiestrogenic effects on different tissues, tamoxifen is the prototypical agent of a class of pharmaceuticals known as selective estrogen receptor modulators (SERMs). It is chemically linked to another antiestrogen, clomiphene. Men and postmenopausal women both use tamoxifen as their main hormonal treatment for metastatic estrogen receptor (ER)positive breast cancer. Giving tamoxifen to women with ERpositive tumors and giving the medicine for five years rather than one to three years yields more advantages. In women at great risk of developing ER-positive breast cancer, Tamoxifen has been shown to reduce its incidence. It doesn’t influence the progression of ERnegatif disease. A new study is now underway to investigate the advantages of tamoxifen versus raloxifene in the prevention of breast cancer (The Study of Tamoxifen and Raloxifene, Initial findings Comparing tamoxifen or anastrozole to the combination of anastrozole and tamoxifen in postmenopausal women with in the ATAC (Arimidex, Tamoxifen, Alone or in Combination) experiment Early breast cancer: The combination arm was terminated early as an efficacy benefit over tamoxifen therapy alone was not shown. Additionally, anastrozole monotherapy after Compared to tamoxifen treatment, patients with a median of 5 years showed an improved survival advantage (hazard ratio 0.87, 95% confidence interval 0.78—0.97, p=0.0127). The tamoxifen only arm had an elevated incidence of vaginal symptoms, thromboembolic incidents, stroke, and endometrial cancer. Patients getting anastrozole, however, had an increased Incidences of hypercholesterolemia, joint problems (such arthralgia, arthritis), and fractures—including wrist, hip, and spine fractures—are all comparable. The other aromatase has shown comparable results. In postmenopausal women with early breast cancer, inhibitors—exemestane and letrozole—compared to tamoxifen. Tamoxifen was first FDA-approved in 1977. An oral solution Approved by the FDA on October 29, 2005, (Soltamox™) is to be distributed with each prescription and prescription renewal for chosen women. A MedGuide is available for tamoxifen.
Tamoxifen possesses both agonistic and anti-estrogenic characteristics. Tamoxifen attaches to oestrogen receptors (ER) and causes conformational changes in the receptor. For instance, tamoxifen activates ER in bone and perhaps helps to stop postmenopausal osteoporosis with antiestrogenic effects on breast tissue. Tamoxifen and other medications’ capacity to generate both estrogenic and antiestrogenic effects most probably comes from contact with other coactivators or corepressors. Binding with various estrogen receptors, ERalpha or ERbeta, in the tissue. The tissue distribution of ERalpha and ERbeta points to distinct activities for these receptors.
Following tamoxifen ER binding, the expression of estrogen dependent genes (RNA transcription) is blocked or modified. The activity of the medication in the nucleus slows cell cycling; hence tamoxifen is cytostatic. Tamoxifen also influences other growth Variables. Tamoxifen causes the secretion of transforming growth factor and lowers insulinlike growth factor type 1, a factor that encourages the development and development of cancer cells. beta (TGFbeta) is linked with suppression of breast cancer cell activity. Reexpression of the tumor suppressor gene maspin is also caused by tamoxifen. The existence of maspin has been demonstrated to stop tumor invasion and metastases; the use of tamoxifen reintroduces maspin into breast cancer cells and may cause the carcinoma to be less invasive.
Important Information About Tamoxifen
Before starting tamoxifen, it’s important to tell your healthcare provider if you have any of the following conditions: blood clots or blood disorders, cataracts or vision problems, endometriosis, high calcium or cholesterol levels, irregular menstrual cycles, liver disease, stroke, uterine fibroids, or if you’ve had any unusual or allergic reactions to tamoxifen or similar medicines. While taking tamoxifen, you will need regular check-ups and blood tests to monitor your health.
Tamoxifen can rarely affect your liver, so your doctor will check your liver function from time to time during treatment.
Like other medicines that affect estrogen, tamoxifen can increase the risk of blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE). Studies have shown that women over 50 taking tamoxifen have a higher chance of developing blood clots or stroke.
Tamoxifen is classified as a pregnancy risk category D drug, which means it can harm an unborn baby. Women should avoid becoming pregnant while taking tamoxifen and for at least two months after stopping it. Sexually active women should use barrier or non-hormonal birth control during treatment and for two months afterward. Tamoxifen does not cause infertility and may even increase the chance of ovulation.
It’s not known if tamoxifen passes into breast milk, but because it could harm a nursing baby, breastfeeding is not recommended while on tamoxifen.
Tamoxifen has been linked to an increased risk of certain uterine problems, including cancer, especially with long-term use. If you have a history of uterine issues, your doctor may suggest other options. While taking tamoxifen, it’s important to report any unusual vaginal bleeding, pelvic pain, or changes in menstrual cycles to your healthcare provider.
Your doctor will monitor your blood regularly to watch for any issues.
Tamoxifen can also affect your eyes, causing cataracts or other vision changes. If you notice any vision problems, tell your doctor.
Some patients with bone metastases may experience high calcium levels early in treatment, so your doctor will monitor this closely.
Tamoxifen’s safety in children is not well established, and long-term effects in young girls are still being studied.
Numerous medicines from many groups interact with tamoxifen citrate; give your doctor a thorough inventory of all the drugs, herbs, vitamins, Nonprescription medications, or nutritional supplements you consume Inform them also whether you smoke, consume alcohol, or take illegal drugs. Certain things might interact with your drug.
In vitro experiments also revealed that erythromycin, cyclosporine, nifedipine, and diltiazem competatively suppressed Ndesmethyl tamoxifen production with respective apparent K_1 values of 20, 1, 45, and 30 µM. The clinical relevance of these in vitro experiments is not clear.
When taken together, tamoxifen lowered the plasma concentration of letrozole by 37%. Aminoglutethimide lowers tamoxifen and Ndesmethyl Tamoxifen plasma concentration. Medroxyprogesterone lowers Ndesmethyl plasma concentrations but not tamoxifen.
Possible Side Effects of This Medicine
Like all medications, this medicine can cause side effects. It’s important to know what to watch for and when to contact your healthcare provider.
Common Side Effects
Many people experience fatigue or tiredness while taking this medicine. Some may notice mild hair thinning or hair loss, though this is uncommon and usually not severe. Headaches and hot flashes are also fairly common. Some men may experience impotence or difficulty with sexual function. Mild nausea or vomiting can occur but usually doesn’t last long. Women might notice vaginal discharge as well.
Changes in Menstrual Cycle and Vaginal Symptoms
Women taking this medicine may experience changes in their menstrual cycle, including irregular periods or even missed periods. If you notice any unusual vaginal bleeding—such as bleeding that is heavy, brown, or rusty—or any pelvic pain or pressure, it’s important to tell your doctor right away.
Serious Side Effects to Watch For
Changes in vision, such as blurred vision
Difficulty breathing or shortness of breath
Trouble walking or talking
New lumps in the breast area
Redness, blistering, peeling, or loosening of the skin, including inside your mouth
Skin rash or itching, especially hives
Sudden chest pain
Swelling of the lips, face, or tongue
Swelling, pain, or tenderness in your calf or leg
Unusual bruising or bleeding
Vaginal discharge that is bloody, brown, or rust-colored
These symptoms could indicate serious allergic reactions, blood clots, or other urgent medical conditions.
Pain and Injuries
In clinical studies, about 16% of postmenopausal women reported pain while taking this medicine. Accidental injuries were also reported in about 10% of women, so it’s important to be cautious and avoid situations where you might fall or hurt yourself.
Effects on Kidneys and Growths
Some women experienced a slight increase in creatinine, a marker of kidney function, but this was uncommon. Growths such as cysts or tumors were reported in a small number of patients.
Effects on the Uterus and Reproductive System
This medicine can cause changes in the uterus, including increased uterine size and the development of cysts. It may also increase the risk of uterine cancers, such as endometrial adenocarcinoma and uterine sarcoma, especially with long-term use. Because of this, women should have regular gynecological exams and report any abnormal vaginal bleeding, pelvic pain, or changes in vaginal discharge to their healthcare provider promptly.
Blood Clots and Stroke
There is an increased risk of blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE), as well as stroke. This risk may be higher if you are also receiving chemotherapy.
Effects on Blood Counts
This medicine can affect your blood cells, sometimes causing low white blood cells (which fight infection), low red blood cells (anemia), or low platelets (which help with clotting). Rarely, this can lead to bleeding problems.
Bone and Muscle Pain
Some patients report bone pain, joint pain, or muscle aches. These symptoms often improve over time but should be discussed with your doctor if they become severe.
Gastrointestinal Symptoms
Nausea is common, and some people may experience vomiting, abdominal pain, constipation, diarrhea, or indigestion. These symptoms are usually mild and manageable.
Mood and Nervous System Effects
Mood changes such as depression, anxiety, or irritability have been reported. Some people also experience headaches, dizziness, or trouble sleeping.
Skin and Hair Changes
Skin rashes, itching, and increased sweating can occur. Hair thinning or hair loss is possible but uncommon. Rarely, serious skin reactions have been reported.
Respiratory Symptoms
These are usually mild but should be reported if persistent or severe.
Weight Changes
Weight gain or weight loss can occur during treatment.
What to Do If You Experience Side Effects
Always tell your healthcare provider about any side effects you experience, especially if they are severe or don’t go away. Some side effects may require medical treatment or a change in your medication.
If you notice any signs of a serious allergic reaction, blood clot, or other urgent symptoms listed above, seek medical help immediately.
Important Information About Tamoxifen
Before starting tamoxifen, it’s important to tell your healthcare provider if you have any of the following conditions: blood clots or blood disorders, cataracts or vision problems, endometriosis, high calcium or cholesterol levels, irregular menstrual cycles, liver disease, stroke, uterine fibroids, or if you’ve had any unusual or allergic reactions to tamoxifen or similar medicines. While taking tamoxifen, you will need regular check-ups and blood tests to monitor your health.
Tamoxifen can rarely affect your liver, so your doctor will check your liver function from time to time during treatment.
Like other medicines that affect estrogen, tamoxifen can increase the risk of blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE). This risk is higher if you’re also receiving chemotherapy. Because of this, tamoxifen should not be used by women who need blood thinners like coumarin or who have a history of blood clots. Studies have shown that women over 50 taking tamoxifen have a higher chance of developing blood clots or stroke.
Tamoxifen is classified as a pregnancy risk category D drug, which means it can harm an unborn baby. Women should avoid becoming pregnant while taking tamoxifen and for at least two months after stopping it. Sexually active women should use barrier or non-hormonal birth control during treatment and for two months afterward. Tamoxifen does not cause infertility and may even increase the chance of ovulation.
It’s not known if tamoxifen passes into breast milk, but because it could harm a nursing baby, breastfeeding is not recommended while on tamoxifen.
Tamoxifen has been linked to an increased risk of certain uterine problems, including cancer, especially with long-term use. If you have a history of uterine issues, your doctor may suggest other options. While taking tamoxifen, it’s important to report any unusual vaginal bleeding, pelvic pain, or changes in vaginal discharge to your healthcare provider promptly.
Your doctor will monitor your blood regularly to watch for any issues.
Tamoxifen can also affect your eyes, causing cataracts or other vision changes. If you notice any vision problems, tell your doctor.
Some patients with bone metastases may experience high calcium levels early in treatment, so your doctor will monitor this closely.
Tamoxifen’s safety in children is not well established, and long-term effects in young girls are still being studied.
Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond use date. Do not flush unused medications or pour down a sink or drain.
- Early Breast Cancer Trialists’ Group. Tamoxifen for early breast cancer: an overview of the randomised trials. Lancet 1998;16:1451-67.
- Fisher B, Costantino JP, Wickerman L, et al. Tamoxifen for the prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 study. J Natl Cancer Inst 1998;90:1371-88.
- Khalkhali-Ellis Z, Christian AL, Kirschmann DA, et al. Regulating the tumor suppressor gene maspin in breast cancer cells. Clinical Cancer Research 2004;10:449-54.
- Kinsinger LS, Harris R, Woolf SH, et al. Chemoprevention of breast cancer: a summary of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med 2002;137:59-67.
- Tewari K, Bonebrake RG, Asrat T, et al. Ambiguous genitalia in an infant exposed to tamoxifen in utero. Lancet 1997;350:183.
- Tamoxifen package insert. Sellersville, PA: Teva Pharmaceuticals USA; 2008 Aug.
- Shaaban MM. Suppression of lactation by an antiestrogen, tamoxifen. Eur J Obstet Gynecol Reprod Biol 1975;4:167-9.
- Tamoxifen tablets package insert. Morgantown, WV: Mylan Pharmaceuticals Inc.; 2013 Apr.
- Litovitz TL, Klein-Schwartz W, Oderda GM, et al. Ipecac administration in children younger than 1 year of age. Pediatrics 1985;76(5):761-764.
