Toremifene, properties

Tamoxifen is a competitive partial agonist inhibitor of estradiol at the estrogen receptor and is extensively used in the palliative treatment of advanced breast cancer in postmenopausal women. It is a nonsteroidal agent (see structure below) that is given orally. Peak plasma levels are reached in a few hours. Tamoxifen has an initial half-life of 7-14 hours in the circulation and is predominantly excreted by the liver. It is used in doses of 10-20 mg twice daily. Hot flushes and nausea and vomiting occur in 25% of patients, and many other minor adverse effects are observed. Studies of patients treated with tamoxifen as adjuvant therapy for early breast cancer have shown a 35% decrease in contralateral breast cancer. However, adjuvant therapy extended beyond 5 years in patients with breast cancer has shown no further improvement in outcome. Toremifene is a structurally similar compound with very similar properties, indications, and toxicities. 

The interesting property of toremifene is the reduced liver carcinogenicity in the rat [284, 285], Toremifene produces fewer DNA adducts than tamoxifen [284] however, there are reports of DNA damage [286] and the drug can still act as an... 

Kangas, L. (1990) Review of the pharmacological properties of toremifene. Journal of Steroid Biochemistry, 36, 191-195. 

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