Tamoxifen Medications

Tamoxifen is a selective estrogen receptor modulator used to treat hormone receptor-positive breast cancer by blocking estrogen's effects on breast tissue cells.

Nolvadex

Tamoxifen

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10 | 20mg

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Tamoxifen Compound Information

Tamoxifen is a selective estrogen receptor modulator (SERM) that plays a central role in the management of estrogen-responsive breast cancer. By binding to estrogen receptors, it blocks the hormone’s proliferative effect in breast tissue while preserving estrogenic activity in bone and the cardiovascular system. The drug is widely prescribed under brand names such as Nolvadex and is also available as a generic product, making it a cornerstone of both adjuvant and metastatic therapy. In addition to its oncological use, tamoxifen is employed off-label for infertility treatment and, in some cases, to mitigate gynecomastia in men. Its dual agonist-antagonist profile underlies both its therapeutic benefits and its safety considerations, which will be outlined in detail## What is Tamoxifen?

Tamoxifen belongs to the class of selective estrogen receptor modulators, agents that exhibit tissue-specific estrogenic or anti-estrogenic activity. The Singapore Health Sciences Authority (HSA) approved tamoxifen in 1992 for the treatment of estrogen receptor-positive (ER⁺) breast cancer, and the indication has expanded to include adjuvant therapy after surgery, treatment of metastatic disease, and risk reduction in high-risk women. The U.S. FDA first approved the drug in 1977, and the European Medicines Agency (EMA) subsequently endorsed its use for similar indications.

At the molecular level, tamoxifen competes with estradiol for binding to the estrogen receptor (ER). In breast tissue, the resulting tamoxifen-ER complex adopts a conformation that recruits corepressors, thereby inhibiting transcription of genes that drive cell proliferation. Conversely, in bone, the uterus and the liver, the complex favors co-activator binding, preserving estrogen’s beneficial effects on bone density lipid metabolism. This selective activity explains why tamoxifen reduces breast cancer recurrence while maintaining bone health.

Tamoxifen is marketed worldwide under the proprietary name Nolvadex and as generic tamoxifen tablets. Both branded and generic versions can be sourced through our online pharmacy, ensuring patients in Singapore have reliable access to the medication.

How Tamoxifen Works

Mechanism of Action

Tamoxifen binds competitively to the ligand-binding domain of estrogen receptors α and β. In breast tissue, the ligand-receptor complex undergoes a conformational shift that disables the activation function-2 (AF-2) domain, preventing co-activators. This blockade halts the expression of cyclin D1, c-Myc and other proliferative genes, leading to cell-cycle arrest and apoptosis of ER⁺ tumor cells.

Therapeutic Effects

By antagonizing estrogen in the mammary gland, tamoxifen reduces the risk of disease recurrence by approximately 40 % in early-stage breast cancer, as demonstrated in the NSABP B-14 trial. In metastatic settings, the drug prolongs progression-free survival by several months and extends overall survival, especially when combined with ovarian suppression in premenopausal women. Its partial agonist activity in bone maintains cortical thickness and reduces fracture risk, an advantage over aromatase inhibitors in certain patient populations.

Onset and Duration

Therapeutic plasma concentrations are reached within 4-6 hours after oral administration, and steady-state levels are achieved after 7-10 days of daily dosing. Clinical benefits in adjuvant therapy become evident within the first year of treatment, while reductions in contralateral breast cancer risk continue throughout the typical 5-year course. The drug’s half-life averages 5-7 days due to extensive enterohepatic recirculation, allowing once-daily dosing with prolonged receptor occupancy.

Approved Uses and Applications

Approved Indications

Adjuvant treatment of ER⁺ invasive breast cancer (post-surgery, with or without chemotherapy). HSA cites this as first-line hormonal therapy for pre- and post-menopausal women.
Metastatic ER⁺ breast cancer - tamoxifen is effective as monotherapy or in combination with ovarian suppression agents.
Risk reduction - indicated for women at high familial or genetic risk of developing breast cancer, based on data from the IBIS-II trial showing a 50 % risk reduction after 5 years.
Male breast cancer - approved for use in men with ER⁺ disease, given the same biological rationale.

Off-Label Uses

Infertility - low-dose tamoxifen (10-20 mg daily) is sometimes prescribed to stimulate ovulation in women with anovulatory cycles, supported by several small randomized trials.
Gynecomastia - used in teenage and adult males to counteract estrogen-driven breast tissue growth, though this indication lacks formal regulatory endorsement.

Clinical Efficacy

In the pivotal ATLAS trial, extending tamoxifen therapy from 5 to 10 years reduced breast cancer recurrence by 4.1 % and mortality by 2.8 % compared with 5-year treatment alone. The SEER database analysis confirmed a 30 % improvement in 10-year survival for patients receiving tamoxifen as adjuvant therapy. These outcomes underscore tamoxifen’s durable benefit when adherence is maintained.

Buying Tamoxifen from Our Online Pharmacy

Why Choose Our Service

Access to tamoxifen can be challenging due to stock fluctuations and pharmacy closures. Our online pharmacy bridges that gap, offering a discreet, secure platform that delivers directly to your doorstep. By leveraging bulk purchasing agreements, we keep prices lower than many brick-and-mortar outlets, helping you stay on therapy without financial strain.

Brand Names and Generic Options

Nolvadex (brand) - widely recognized, high-quality tablet formulation.
Tamoxifen (generic) - chemically identical, typically priced 30-40 % less than the branded version.
Soltamox - another reputable brand available in certain Asian markets, offered through our network.

Quality & Safety

We partner with licensed international pharmacies that operate under stringent regulatory frameworks, including compliance with WHO Good Manufacturing Practice (GMP) standards. Every batch undergoes third-party verification before shipment.

Pricing & Access

Our platform lists tamoxifen at competitive rates, with a “Lifetime 10 % discount on all reorders” for returning customers. Express shipping averages 7 days, while standard delivery arrives within three weeks. All orders are packaged in plain, tamper-evident containers to protect your privacy.

Dosing, Formulations & Administration

Available Formulations

Tamoxifen is supplied as oral tablets in strengths of 10 mg, 20 mg and 40 mg. The tablets are film-coated, swallow-whole, and contain no lactose or gluten.

Typical Dosing Ranges

For adjuvant breast cancer therapy, clinicians commonly start with 20 mg once daily and may continue for five to ten years, adjusting based on tolerability and hepatic function. In infertility protocols, doses range from 10 mg to 20 mg daily for a limited cycle of three to six months. These examples reflect standard practice; a qualified healthcare professional must individualize dosing.

Administration Guidelines

Tamoxifen may be taken with or without food; however, a high-fat meal can modestly increase absorption, potentially accentuating side effects. Consistency is key-take the tablet at the same time each day to maintain stable plasma levels. Patients should avoid abrupt discontinuation, as sudden hormone shifts can provoke flare-ups.

A healthcare provider must determine the exact dose and schedule based on your medical history, concomitant medications, and treatment goals.

Safety Profile & Considerations

Common Side Effects

Hot flashes - reported in ~40 % of patients; typically milder after the first few months.
a - occurs in 10-20 % of users; can be mitigated with meals or anti-emetics.
Vaginal dryness or discharge - estrogen antagonism in the genital tract affects 5-10 % of women.
Fatigue - noted in up to 15 % of patients, often transient.

Serious Adverse Events

Endometrial cancer - tamoxifen’s agonist effect on uterine tissue raises risk; incidence rises to ~3 % after five years of therapy. Any abnormal uterine bleeding should prompt immediate evaluation.
Venous thromboembolism (VTE) - deep-vein thrombosis and pulmonary embolism occur in 1-2 % of patients, necessitating prompt medical attention if leg swelling or sudden shortness of breath develop.
Cataracts - long-term use modestly increases cataract formation; regular ophthalmologic review is advisable.

Contraindications

Known hypersensitivity to tamoxifen or its excipients.
Active or past history of thromboembolic disease (e.g., DVT, PE).
Pregnant or breastfeeding women - tamoxifen is teratogenic and excreted in breast milk.

Drug Interactions

CYP2D6 inhibitors (e.g., fluoxetine, paroxetine) reduce conversion of tamoxifen to its active metabolite endoxifen, potentially diminishing efficacy.
Anticoagulants - concurrent use may enhance bleeding risk; INR should be monitored closely.
Tamoxifen + warfarin - may increase INR; periodic testing required.

Special Populations

Pregnancy & breastfeeding - contraindicated; a 2-year washout is recommended before conception.
Elderly - increased VTE risk; dose adjustments may be needed for renal or hepatic impairment.
Hepatic dysfunction - tamoxifen is metabolized hepatically; severe liver disease may require dose reduction or alternative therapy.

Frequently Asked Questions

What differentiates tamoxifen from aromatase inhibitors? Tamoxifen blocks estrogen receptors directly, while aromatase inhibitors lower systemic estrogen levels by inhibiting its synthesis. The choice depends on menopausal status and individual risk profiles.
How long before tamoxifen produces noticeable effects for breast cancer? Clinical benefit in reducing recurrence becomes evident after the first year of continuous therapy, though plasma levels stabilize within a week of daily dosing.
What should I do if I experience severe hot flashes while taking tamoxifen? Discuss dose timing, lifestyle modifications (e.g., layered clothing, cooling fans) and possible adjunctive medications such as low-dose antidepressants with your clinician.
Can tamoxifen cause weight gain? Weight changes are not a prominent side effect, but some patients report modest fluid retention; regular exercise and balanced nutrition can help manage this.
Is it safe to take tamoxifen with hormonal contraceptives? Contraceptives do not interfere with tamoxifen’s efficacy, but estrogen-containing pills may modestly increase VTE risk; a barrier method may be preferable during therapy.
Does taking tamoxifen with food affect its absorption? High-fat meals can increase absorption slightly, but the effect is clinically insignificant; consistency in taking the medication with or without food is more important.
What are the signs of a serious allergic reaction to tamoxifen? Look for rash, itching, swelling of the face or throat, and difficulty breathing. Seek emergency care immediately if these occur.
How often should I have gynecological monitoring while on tamoxifen? Annual pelvic examinations and endometrial ultrasound are recommended after five years of therapy, or sooner if abnormal bleeding arises.
What information should I provide my doctor when discussing tamoxifen?
- Complete list of current prescription, over-the-counter and herbal medications.
- History of blood clots, liver disease, or uterine abnormalities.
- Reproductive plans, including desire for pregnancy.
- Any previous hormonal therapies and their outcomes.

Disclaimer

The information provided about tamoxifen is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing tamoxifen for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing tamoxifen.