Dosing and uses of Fareston (toremifene)
Adult dosage forms and strengths
tablet
- 60mg
Breast Cancer
60 mg PO qD until disease progresses
Monitor: patients on warfarin for increased Pt
Desmoid Tumors (Orphan)
Indicated for treatment of desmoid tumors
Orphan indication sponsor
- Orion Corporation; PO Box 65; 02101 Espoo; FINLAND
Other Indications & Uses
Estrogen-receptor positive or unknown metastatic breast cancer in postmenopausal women
Pediatric dosage forms and strengths
Not recommended
Fareston (toremifene) adverse (side) effects
>10%
Hot flashes (35%)
Sweating (20%)
Nausea (14%)
Vaginal discharge (13%)
1-10%
Cataracts (10%)
Dizziness (9%)
Edema (5%)
Vomiting (4%)
Dry eyes (4%)
Hypercalcemia (3%)
Thrombophlebitis (2%)
Vaginal bleeding (2%)
Warnings
Black box warnings
Prolongs QTc interval in a dose- and concentration-related manner
QT prolongation can result in Torsade de pointes, which may result in syncope, seizure, and/or death
Should not be prescribed to patients with congenital/acquired QT prolongation, uncorrected hypokalemia or uncorrected hypomagnesemia
Drugs known to prolong QT interval and strong CYP3A4 inhibitors should be avoided
Contraindications
Hypersensitivity
Estrogen receptor-negative tumors
Thromboembolic history
Should not be prescribed to patients with congenital/acquired QT prolongation, uncorrected hypokalemia or uncorrected hypomagnesemia
Cautions
May increase risk of ovarian CA, osteosarcoma
Risk of hypercalcemia & tumor flare
Long-term Tx discouraged in preexisting endometrial hyperplasia
Prolongs QTc interval; avoid in patients with congenital/acquired QT prolongation or uncorrected hypokalemia/hypomagnesemia
Avoid concomitant use of drugs known to prolong QT intervaL
Pregnancy and lactation
Pregnancy category: d
Lactation: not known if excreted in breast milk, indicated in postmenopausal women
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Fareston (toremifene)
Half-Life: 5 d
Peak Plasma Time: 3 hr
Protein Bound: >99.5%
Vd: 580 L
Metabolism: hepatic CYP3A4
Metabolites: N-demethyltoremifene, (deamino-hydroxy) toremifene
Clearance: 5 L/hr
Excretion: feces
Mechanism of action
Selective estrogen receptor modulator: nonsteroidal estrogen, agonist/antagonist, competes for estrogen binding sites on breast tumor cells
