Medication Description: Phosphostrol (Phosphoestrolum)
Tetrasodium salt of diphosphoric ester trans-3, 4-di-para-hydroxyphenylhexene-3.
Synonyms: Honwan, Cytonal, Difostilben, Fosfestrol, Fosfostiben, Honvan, Honvol, Stibostatin, Stilphostrol, etc.
White or white with a creamy tinge crystalline powder. Easily soluble in water, practically insoluble in alcohol.
According to the structure, phosphestrol is a diethylstilbestrol phosphoric ester (see).
Phospestrol (honvan) is used to treat prostate cancer (including cases with metastases). It is considered a specific agent acting in all stages of cancer of this localization, sensitive to estrogen drugs. With estrogen-resistant forms of the tumor, phospestrol is ineffective.
Phospestrol was synthesized to create an estrogen preparation with selective antitumor activity, namely, that it was inactive during circulation in the blood, but when the prostate gland penetrates into the tumor tissue, it decomposes under the influence of the phosphatase contained in it (the activity in the tumor cells) with the release of diethylstilbestrol, providing a cytostatic effect. Thus, phospestrol can be considered as a prodrug that performs the <transport> function, i.e. delivering the active substance to the tumor tissue. According to the principle of construction, fosfestrol thus has similarities with cyclophosphamide (see).
Phosphestrol is administered intravenously in the form of a 6% solution and inwards in the form of tablets.
There are different patterns of phospestrol (honwana). Usually, treatment begins with a daily intravenous dose of 1, 2 g (4 ampoules of 0.3 g each). Enter slowly or drip, diluting in 5% glucose solution (with the patient lying down) for 10 days, then 0.3 g (1 ampoule per day) for 10 to 20 days. In special cases, use the drug daily for a long time.
Weakened patients, people with heart failure, impaired liver and kidney function, the drug begins to be administered in smaller doses - 0.6 g (2 ampoules of 0.3 g) per day for 10 days, then 0.3 g (1 ampoule ) in a day.
Reducing the dose of phosphestrol (honwana) should be carried out under the control of clinical and biochemical parameters; should determine the level of acid phosphatase in the serum.
If intravenous administration is not possible, phospestrol (hwan) is administered orally in the form of tablets (before meals with a small amount of liquid).
Take 3 - 4 tablets (0.1 g per tablet) 3 times a day. In the case of the development of dyspeptic symptoms, it is recommended to hold the pills on the cheek or under the tongue until complete resorption.
For maintenance therapy, 1 to 2 tablets are prescribed 3 times a day, then 1 tablet 2 times a day (no less). You can carry out maintenance therapy with injections of phospestrol (honvana) at 0.3 g 4 - 3 - 2 - 1 once a week (under the control of clinical and biochemical parameters).