Emcyt (estramustine phosphate sodium)

Estramustine phosphate sodium, a complex of 17 beta-estradiol and nornitrogen mustard, is an antimicrotubule antineoplastic agent.

Estramustine phosphate sodium, a complex of 17 beta-estradiol and nornitrogen mustard linked together by a carbamate ester bridge, is an antimicrotubule antineoplastic agent. While the exact mechanisms of action are complex and have not been fully elucidated, the beneficial effects of estramustine in the palliative treatment of prostate cancer generally are believed to result from the drug's cytotoxic and antigonadotropic activities.

Following oral administration, estramustine phosphate sodium is rapidly dephosphorylated in the GI tract to estramustine, most of which is subsequently oxidized to an active cytotoxic metabolite, estromustine. Estramustine and estromustine exert their cytotoxic effects principally by binding to tubulin and/or microtubule-associated proteins. Binding of estramustine or estromustine to these protein subunits induces depolymerization of microtubules, resulting in cellular metaphase arrest.

The antimicrotubule effects of estramustine appear to be related principally to the intact estramustine or estromustine complex; only a minor cytotoxic effect has been associated with the nornitrogen mustard moiety. Limited data indicate that the drug also may damage the cell membrane, promote DNA breakage, interfere with DNA replication, and induce cellular apoptosis in other cell lines (e.g., glioma cells, colon cancer cells).

Approximately 10-20% of estramustine or estromustine is metabolized to estradiol or estrone, respectively. Markedly elevated estradiol concentrations have been detected as early as 1 week following initiation of estramustine therapy and may persist for 7-12 weeks following discontinuance of the drug. Estradiol and estrone exert antigonadotropic effects and have been shown to decrease plasma concentrations of testosterone, dihydrotestosterone, gonadotropins, cholesterol, and 17-hydroxyprogesterone; estradiol and estrone also may increase prolactin and cortisol concentrations.

Because total plasma concentrations of estradiol during prolonged therapy with estramustine increase to levels similar to those achieved with conventional estradiol therapy, estrogenic effects may be similar in patients receiving estramustine and in those receiving oral estradiol. Some data indicate that reductions in testosterone concentrations associated with estramustine therapy may be comparable to or greater than those achieved after surgical castration.

Estramustine and estromustine and their metabolites are excreted principally in bile; a small amount (less than 1%) of conjugated estradiol and estrone is excreted in urine.

Generic name: estramustine phosphate sodium

The following indications are listed for Emcyt:

• Prostatic Carcinoma

Also known as: Malignancy Of Prostate, Malignant Neoplasm Of Prostate, Malignant Tumor Of Prostate, Prostate Cancer.

No ICD codes are available for this drug.