Fosfestrol is a hormonal chemotherapy medication containing the active constituent fosfestrol. It is a synthetic estrogen-like medication that has been used to treat certain types of advanced prostate and breast cancer. The prostate is a gland surrounding the urethra just below the bladder. The prostate produces the seminal fluid which nourishes the sperm. In prostate cancer, patients experience trouble urinating, blood in urine and semen, bone pain, weight loss, and erectile dysfunction. 

Fosfestrol was approved by the FDA on December 20, 1957, for the treatment of advanced prostate cancer. It may also be used in combination with other medications or treatments to further improve outcomes for patients. Fosfestrol can be a useful treatment option for men who are unable to undergo surgery or radiation therapy, or who have not responded well to other forms of chemotherapy.

Fosfestrol is used for the treatment of advanced prostate cancer and advanced breast cancer.

Fosfestrol is an oral medication usually taken once a day, at approximately the same time each day, with or without food. It should be taken as prescribed by a doctor or other healthcare provider. These capsules should be swallowed whole with a glass of water. They should not be crushed, chewed, or opened, as this can affect the way the medication is absorbed and decrease its effectiveness. You should not take a double dose to make up for the second dose.

Fosfestrol, like all medications, can cause side effects. Some of the more serious side effects include blood clots, stroke, heart attack, and liver damage. These side effects are rare, but they can be severe and potentially life-threatening. Other common side effects may include nausea, vomiting, diarrhea, loss of appetite, weight loss, hot flashes, impotence, and breast enlargement in men. It can also cause changes in blood chemistry, such as elevated levels of calcium and phosphorus, which can lead to bone pain, kidney damage, and other complications.

Fosfestrol can increase the risk of blood clots, which can lead to serious health problems such as stroke, heart attack, or pulmonary embolism (blood clot in the lung). This medication can affect blood sugar levels and can worsen diabetes in some patients which in turn results in an increased risk of infection and poor wound healing. It can cause changes in vision, including blurred vision or loss of vision. In rare cases, this medication results in osteoporosis (bone loss) and increases the risk of fractures.

Fosfestrol can increase the risk of blood clots, which can lead to serious health problems such as stroke, heart attack, or pulmonary embolism (blood clot in the lung). This medication can affect blood sugar levels and can worsen diabetes in some patients which in turn results in an increased risk of infection and poor wound healing. It can cause changes in vision, including blurred vision or loss of vision. In rare cases, this medication results in osteoporosis (bone loss) and increases the risk of fractures.

If you are receiving treatment with fosfestrol, report any side effects or concerns promptly. To reduce your risk of falls and fractures, you should take steps such as using assistive devices, wearing appropriate footwear, and participating in regular physical activity as recommended by your healthcare provider. If you are pregnant or planning to become pregnant, or if you are breastfeeding, it is important to discuss the risks and benefits with your healthcare provider. Reproductive-age women should use effective birth control during the treatment and for at least two weeks after their last dose. Making lifestyle changes, such as quitting smoking, maintaining a healthy weight, and eating a healthy diet, can also help support your overall health and reduce the risk of complications associated with cancer.

1. KD Tripathi, Essentials of Medical Pharmacology, Anticancer drugs, 7th edition, 2013, 872.
2. Chabner, B. A., & Longo, Cancer Chemotherapy and Biotherapy: Principles and Practice, 6 edition, 2019, 700-701.
3. Kaye, S. B., Kerr, D. J., & Tait, D, Textbook of Medical Oncology, 4th edition, 2015, 305-306.
4. DeVita, V. T., Lawrence, T. S., & Rosenberg: Principles & Practice of Oncology, 10th edition, 2015, 922-923.
5. Mauro Orlando et al; Low-dose continuous oral fosfestrol is highly active in 'hormone-refractory' prostate cancer; Annals of Oncology; [Published on March 2000]; [Accessed on 22 April 2023], https://www.researchgate.net/publication/12554273_Low-dose_continuous_oral_fosfestrol_is_highly_active_in_'hormone-refractory'_prostate_cancer

The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.