Polyestradiol phosphate

Polyestradiol phosphate (PEP), sold under the brand name Estradurin, is a medication which is used in hormone therapy for the treatment of prostate cancer in men. It is also used in hormone replacement therapy (HRT) for the treatment of menopausal symptoms in women. PEP is an estrogen; specifically, it is a long-acting ester of estradiol, the primary female sex hormone. It works by suppressing the production of testosterone, which plays a key role in the development and progression of prostate cancer. In women, it compensates for the decreased production of estrogen following menopause, alleviating symptoms such as hot flashes, vaginal dryness, and osteoporosis.

Medical uses[edit | edit source]

PEP is primarily used in the treatment of advanced prostate cancer. It provides a method of estrogen therapy that requires less frequent dosing than many other forms of estrogen therapy. In women, PEP is used in HRT to treat symptoms associated with menopause.

Pharmacology[edit | edit source]

Mechanism of action[edit | edit source]

As an estrogen, PEP exerts its effects by binding to and activating the estrogen receptor (ER) in various tissues. In the context of prostate cancer, the activation of ER leads to a decrease in the production of luteinizing hormone (LH) by the pituitary gland, which in turn reduces the production of testosterone by the testes. Since testosterone stimulates the growth of prostate cancer cells, its reduction slows the progression of the disease. In menopausal women, PEP's estrogenic activity helps to alleviate symptoms caused by estrogen deficiency.

Pharmacokinetics[edit | edit source]

After intramuscular injection, PEP is slowly hydrolyzed into estradiol and phosphate in the body. This process provides a steady release of estradiol, ensuring prolonged estrogenic effects. The pharmacokinetics of PEP allow for less frequent dosing schedules compared to other forms of estrogen therapy.

Adverse effects[edit | edit source]

The use of PEP, like other forms of estrogen therapy, can be associated with several adverse effects. These may include nausea, breast tenderness, and an increased risk of thromboembolic events such as deep vein thrombosis (DVT) and pulmonary embolism. In men, feminization effects such as gynecomastia may occur. Monitoring and management of these potential side effects are important aspects of treatment with PEP.

History[edit | edit source]

PEP was first introduced for medical use in the 1950s. It has been used in various countries for the treatment of prostate cancer and menopausal symptoms. Over the years, the understanding of its pharmacology and the management of its adverse effects have evolved, improving its safety and efficacy as a therapeutic agent.