mode of action
Last reviewed 07/2021
This is thought to be via competing with oestradiol for a cytoplasmic receptor. Approximately 50% of patients with advanced breast carcinoma are receptor positive and will respond to tamoxifen therapy. There is a response to treatment in about 15% of patients who are receptor negative.
Tamoxifen and its active metabolite desmethyl tamoxifen both have a t1/2 of approximately 2 weeks. A steady state is not reached until at least 6 weeks after commencing therapy.