TOREMIFENE CITRATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TOREMIFENE CITRATE (TOREMIFENE CITRATE).
Nonsteroidal estrogen receptor antagonist; binds to estrogen receptors (ER) with high affinity, competitively inhibiting estrogen binding and exerting antiestrogenic effects. Also possesses weak estrogenic agonist activity.
| Metabolism | Primarily hepatic via CYP3A4 to N-desmethyltoremifene; also undergoes N-oxide formation. Excreted mainly in feces (75%) and urine (20%). |
| Excretion | Primarily fecal (biliary excretion) as metabolites; approximately 10% renal |
| Half-life | About 5 days for the parent compound; clinical context: steady-state achieved in ~4 weeks |
| Protein binding | >99.5% bound to albumin |
| Volume of Distribution | 580-800 L (approximately 8-12 L/kg); indicates extensive tissue distribution |
| Bioavailability | Oral: approximately 100% (well absorbed) |
| Onset of Action | Oral: within weeks for estrogen receptor antagonism; clinical response may take several weeks |
| Duration of Action | Prolonged due to long half-life; clinical effects persist weeks after discontinuation |
60 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | No adjustment required for any degree of renal impairment |
| Liver impairment | Contraindicated in Child-Pugh class B or C; avoid use |
| Pediatric use | Safety and efficacy not established; no standard pediatric dosing |
| Geriatric use | No specific dose adjustment; monitor for increased adverse effects due to age-related changes in clearance |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TOREMIFENE CITRATE (TOREMIFENE CITRATE).
| Breastfeeding | Excretion in human milk unknown; toremifene is highly protein-bound and lipophilic, likely present in milk. No M/P ratio available. Contraindicated during breastfeeding due to potential serious adverse effects in infant (e.g., hormonal effects). Discontinue nursing or drug. |
| Teratogenic Risk | Toremifene citrate is an antiestrogen; limited human data. In animals, fetal resorptions and developmental delays at doses similar to human exposure. FDA Pregnancy Category D. Avoid in pregnancy; potential for fetal harm, especially in first trimester. Use only if clearly needed. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to toremifene or any component","History of thromboembolic events (e.g., DVT, PE)","Concurrent use with QTc-prolonging drugs (e.g., class IA and III antiarrhythmics, certain antipsychotics, macrolides)","Pregnancy and lactation"]
| Precautions | ["Prolongation of QT interval, especially in patients with electrolyte disturbances or concurrent QT-prolonging drugs","Thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism)","Endometrial hyperplasia and uterine malignancies due to estrogenic activity","Fetal harm if used during pregnancy","Hepatic impairment","Hypercalcemia in patients with bone metastases"] |
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| Fetal Monitoring | Monitor LFTs, CBC, and serum calcium periodically. In pregnancy, assess fetal development via ultrasound if inadvertent exposure. Tumor response evaluation. No specific fetal monitoring required if not pregnant. |
| Fertility Effects | May suppress ovulation due to antiestrogenic effects; can impair fertility in women. Reversible upon discontinuation. Use of contraception recommended during treatment and for 2 months after last dose. No data on male fertility. |