CHLOROTRIANISENE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CHLOROTRIANISENE (CHLOROTRIANISENE).
Synthetic nonsteroidal estrogen; binds to estrogen receptors (ERα and ERβ), activating estrogen-responsive gene transcription, leading to estrogenic effects on reproductive tissues, bone, and other targets.
| Metabolism | Hepatic via hydroxylation and conjugation (glucuronidation and sulfation); undergoes enterohepatic circulation. |
| Excretion | Primarily renal (metabolites, ~60-70%), with biliary/fecal elimination as minor routes (~20-30%). Unchanged drug is minimal in urine; extensive hepatic metabolism occurs. |
| Half-life | Terminal elimination half-life is approximately 10-12 hours, but due to enterohepatic recirculation and accumulation in adipose tissue, effective half-life during chronic dosing may extend to several days. |
| Protein binding | ~90-95% bound, primarily to albumin and sex hormone-binding globulin (SHBG). |
| Volume of Distribution | Vd ranges from 1-2 L/kg, indicating extensive tissue distribution, particularly to adipose tissue. |
| Bioavailability | Oral bioavailability is approximately 30-50%, variable due to first-pass metabolism and food effects. |
| Onset of Action | Oral: Therapeutic effects on estrogen-responsive tissues may be noted within 1-2 weeks, though maximal clinical response often requires 4-8 weeks. |
| Duration of Action | Duration after single dose: estrogenic effects persist for 2-4 weeks due to slow release from adipose stores and enterohepatic recycling. With repeated dosing, effect lasts as long as treatment continues. |
12-25 mg orally once daily for palliation of advanced breast cancer in postmenopausal women; may increase to 25 mg twice daily if no response after 1 month. For prostate cancer, 12-25 mg orally once daily.
| Dosage form | CAPSULE |
| Renal impairment | No specific guidelines; use caution in severe impairment (CrCl <30 mL/min) due to potential accumulation of metabolites; consider dose reduction by 50%. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use. |
| Pediatric use | Not recommended; safety and efficacy not established for any indication. |
| Geriatric use | Initiate at lower end of dosing range (12 mg/day) due to increased risk of thromboembolic events, fluid retention, and hypercalcemia; monitor for adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CHLOROTRIANISENE (CHLOROTRIANISENE).
| Breastfeeding | Contraindicated during breastfeeding. Chlorotrianisene is excreted in breast milk and may cause adverse effects in the nursing infant. M/P ratio not available. |
| Teratogenic Risk | Category X. Contraindicated in pregnancy due to teratogenic and fetotoxic effects. First trimester exposure associated with genital tract abnormalities, congenital heart defects, and cleft palate. Second and third trimester use linked to vaginal adenosis, clear cell adenocarcinoma in female offspring, and increased risk of urogenital anomalies. High risk of fetal harm at any gestational age. |
■ FDA Black Box Warning
None
| Serious Effects |
Known or suspected pregnancy; undiagnosed abnormal genital bleeding; active thromboembolic disorders (e.g., DVT, PE); estrogen-dependent neoplasia (e.g., breast cancer, endometrial cancer); hypersensitivity to chlorotrianisene.
| Precautions | Increased risk of endometrial hyperplasia and endometrial carcinoma; increased risk of thromboembolic events (DVT, PE, stroke); avoid use in pregnancy (fetal harm); caution in hepatic impairment, cardiovascular disease, hypercalcemia, and gallbladder disease. |
| Food/Dietary | No specific food interactions reported. Grapefruit juice may increase estrogen levels; consider avoiding excessive consumption. |
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| Fetal Monitoring | Monitor maternal hepatic function, serum calcium, and coagulation profile. Fetal ultrasonography for anatomical development if inadvertent exposure occurs. Monitor for signs of thromboembolism. |
| Fertility Effects | May impair fertility in females by disrupting normal ovulatory function and endometrial receptivity. In males, may reduce spermatogenesis due to estrogenic effects. Reversible upon discontinuation. |
| Clinical Pearls |
| Chlorotrianisene is a synthetic estrogen used primarily for palliative therapy in advanced prostatic carcinoma. It may increase cardiovascular thrombotic risk. Monitor for signs of thromboembolism and hypercalcemia in patients with bone metastases. |
| Patient Advice | Take this medication exactly as prescribed. · Report symptoms of blood clots (leg pain/swelling, chest pain, sudden shortness of breath) or stroke (sudden weakness, slurred speech) immediately. · Do not take during pregnancy or while breastfeeding. · Inform your doctor if you have a history of blood clots, heart disease, or estrogen-sensitive cancers. · Avoid smoking as it increases the risk of serious side effects. |