Tamoxifen
Administration
- Type: SERM
- Dosage Forms: Tab 10mg, 20mg
- Routes of Administration: Oral
- Common Trade Names: Soltamox
Adult Dosing
Breast Cancer
- 20 mg PO daily
Mastalgia
- 10 mg PO daily x4 months
Pediatric Dosing
Precocious Puberty
- For 2-10 yo
- 20 mg PO daily
Special Populations
Pregnancy Rating
- Category D: avoid use during pregnancy
- Risk of teratogenicity and fetal death
Lactation risk
- Avoid use while breastfeeding
- Decreased milk production
Renal Dosing
- Adult: Not defined
- Pediatric: Not defined
Hepatic Dosing
- Adult: Not defined
- Pediatric: Not defined
Contraindications
- Allergy to class/drug
- Pregnancy
- Breastfeeding
- Undiagnosed vaginal bleeding
- H/o thromboembolism
- Warfarin anticoagulation
Adverse Reactions
Serious
- Thromboembolism
- Stroke
- Endometrial cancer, endometriosis, uterine sarcoma, uterine fibroid, ovarian cyst
- Hypersensitivity, erythema multiforme
- Thrombocytopenia, leukopenia, neutropenia, pancytopenia
- Hepatotoxicity
- Retinopathy, cataracts
Common
- Hot flashes, menstrual irregularities, vaginal bleeding, visual changes
- Nausea/vomiting, lightheadedness, dizziness
- Fatigue, headache, visual acuity changes
- Anorexia
Pharmacology
- Half-life: 5-7 days; active metabolite 14 days
- Metabolism: Liver; CYP450: 2C9, 2D6, 3A4
- Excretion: Feces primarily
Mechanism of Action
- Selectively binds to estrogen receptors, producing estrogenic and anti-estrogenic effects
- Estrogen antagonist in breast cancer cells
- Estrogen antagonist in hypothalamus of premenopausal women
- Unknown mechanism in McCune-Albright syndrome
Comments
See Also
References
Epocrates, UpToDate