Description of the medicine: Phosphestrol (Phosphoestrolum)
Tetrasodium salt of trans-3, 4-di-para-hydroxyphenylhexene-3 diphosphoric ester.
Synonyms: Honwan, Cytonal, Difostilben, Fosfestrol, Fosfostiben, Honvan, Honvol, Stibostatin, Stilphostrol, etc.
Fine crystalline powder, white or white with a creamy tint. Easily soluble in water, practically insoluble in alcohol.
By structure, phosphestrol is a diethylstilbestrol phosphorus ester (see).
Phosphestrol (Honwan) is used to treat prostate cancer (including cases with metastases). It is considered a specific tool that acts in all stages of cancer of this localization, sensitive to estrogen drugs. With estrogen-resistant forms of the tumor, phosphestrol is ineffective.
Fosfestrol was synthesized in order to create an estrogenic drug with selective antitumor activity, namely, to be inactive during circulation in the blood, but when it penetrates into the tumor tissue of the prostate gland it decomposes under the influence of phosphatase contained in it (the activity of which is increased in tumor cells) with the release of diethylstilbestrol, which has a cytostatic effect. Thus, phosphestrol can be considered as a prodrug that performs a "transport" function, i.e. delivering the active substance to the tumor tissue. By the principle of construction, phosphestrol thus has similarities with cyclophosphamide (see).
Fosfestrol is administered intravenously in the form of a 6% solution and orally in the form of tablets.
There are different schemes for the use of phosphestrol (honvana). Typically, treatment begins with daily intravenous administration of 1, 2 g (4 ampoules of 0.3 g). Enter slowly or drip, diluting in a 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, the drug is used 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.
A dose reduction of phosphestrol (honvana) should be carried out under the supervision of clinical and biochemical parameters; serum acid phosphatase levels should be determined.
If intravenous administration is not possible, phosphestrol (honvan) is prescribed 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 dyspeptic symptoms, it is recommended to hold the tablets behind the cheek or under the tongue until completely resorbed.
For maintenance therapy, 1 to 2 tablets are prescribed 3 times a day, then 1 tablet 2 times a day (no less). It is possible to carry out maintenance therapy with injections of phosphestrol (honvana) at 0.3 g 4 - 3 - 2 - 1 times a week (under the control of clinical and biochemical parameters).