Description

Tamoxifen Tablets 20 mg #30

Composition

Each tablet contains 20 mg of tamoxifen (as tamoxifen citrate). Inactive ingredients include corn starch, lactose, magnesium stearate, and pre-gelatinized starch.

Pharmacological Group

Selective Estrogen Receptor Modulators (SERMs)

Mechanism of Action

Tamoxifen acts as a selective estrogen receptor modulator, exhibiting estrogen antagonist effects in breast tissue and agonist effects in other tissues such as bone and endometrium. Its antiestrogenic action helps prevent the growth of estrogen receptor-positive breast cancer cells.

Indications

• Treatment of hormone receptor-positive metastatic breast cancer in men and women
• Adjuvant treatment following surgery and/or radiation in breast cancer
• Risk reduction in high-risk patients for primary breast cancer prevention

Contraindications

• Known hypersensitivity to tamoxifen
• History of deep vein thrombosis or pulmonary embolism
• Concurrent use with coumarin-type anticoagulants
• Pregnancy (Category D)

Dosage and Administration

The standard dose is 20 mg once daily. If a higher dose is required, divide into 10 mg twice daily. Treatment duration depends on indication and patient response.

Pharmacokinetics

• Absorption: Well absorbed orally
• Peak plasma concentration: 4–7 hours
• Metabolism: Hepatic (CYP2D6 and CYP3A4)
• Half-life: Approximately 5–7 days

Precautions

• Monitor for thromboembolic events and endometrial changes
• Use with caution in patients with hepatic impairment
• May affect liver function tests, complete blood counts

Warnings

• May increase risk of uterine malignancies, stroke, and pulmonary embolism
• Not recommended during pregnancy or breastfeeding

Side Effects

• Hot flashes, nausea, fatigue
• Menstrual irregularities, vaginal discharge
• Increased risk of endometrial cancer, thromboembolism
• Rare: ocular toxicity, hepatic dysfunction, hypersensitivity reactions

Drug Interactions

• SSRIs (e.g., paroxetine, fluoxetine) may reduce efficacy by inhibiting CYP2D6
• Anticoagulants: may potentiate bleeding
• Do not use with estrogen-containing products

Overdose

Symptoms may include tremors, dizziness, irregular heartbeat, unsteady gait. In case of overdose, seek emergency medical attention or contact poison control.

Pregnancy and Lactation

• Pregnancy: Category D – evidence of human fetal risk
• Lactation: Not recommended – may interfere with milk production and safety for the infant is unknown

Storage

Store at controlled room temperature (20–25°C). Protect from moisture and light. Keep out of reach of children.

Scientific References

• Fisher B, et al. “Tamoxifen for prevention of breast cancer.” J Natl Cancer Inst. 2005.
• Early Breast Cancer Trialists’ Collaborative Group. “Tamoxifen for early breast cancer: an overview of the randomized trials.” Lancet. 1998.

Disclaimer

This content is for informational purposes only and should not replace consultation with a qualified healthcare provider. Always follow medical advice specific to your condition.