Health and Prostate

Drug Nomenclature

Pharmacopoeias. In British.

British Pharmacopoeia 2008 (Estramustine Sodium Phosphate). A white or almost white powder. Freely soluble in water and in methyl alcohol; very slightly soluble in dehydrated alcohol and in chloroform. A 0.5% solution in water has a pH of 8.5 to 10.0. Protect from light.

Adverse Effects, Treatment, and Precautions

Oestrogenic adverse effects are fairly common, and may include gynaecomastia, fluid retention, and cardiovascular effects. Gastrointestinal disturbances, hepatic dysfunction, loss of libido, hypersensitivity reactions, and occasionally leucopenia and thrombocytopenia may occur. Estramustine is contra-indicated in patients with peptic ulceration and severe hepatic or cardiovascular disease. Diabetes mellitus may be exacerbated, and the drug should be given with care to patients with disorders such as congestive heart failure, epilepsy, hypertension, migraine, and renal impairment which may be adversely affected by additional fluid retention. Care is also required in patients with conditions predisposing to hypercalcaemia, and serum calcium should be monitored in hypercalcaemic patients.

Porphyria. Estramustine has been associated with acute attacks of porphyria and is considered unsafe in porphyric patients.

Interactions

Estramustine sodium phosphate should not be given with milk products or products high in calcium, which may interfere with its absorption. Hypersensitivity reactions including angioedema have occurred rarely in patients given estramustine who were also receiving an ACE inhibitor.

Pharmacokinetics

Up to 75% of a dose of estramustine sodium phosphate is absorbed from the gastrointestinal tract and rapidly dephosphorylated. Estramustine is found in the body mainly as its oxidised isomer estromustine; both forms accumulate in the prostate. Some hydrolysis of the carbamate linkage occurs in the liver, releasing estradiol, estrone, and the normustine group. Estramustine and estromustine have plasma half-lives of 10 to 20 hours, and are excreted with their metabolites mainly in the faeces.

Uses and Administration

Estramustine is a combination of estradiol and normustine and has weaker oestrogenic activity than estradiol and weaker antineoplastic activity than most other alky fating agents. Estramustine phosphate is given orally as the disodium salt. Doses are calculated in terms of estramustine phosphate; 108 mg of estramustine sodium phosphate is equivalent to about 100 mg of estramustine phosphate. Estramustine phosphate with meglumine has been given by intravenous injection.

Estramustine sodium phosphate is licensed for use in the treatment of advanced prostatic carcinoma. An estramustine phosphate dose of about 14 mg/kg daily in divided doses is used. The usual initial dose is 560 to 840 mg daily, which may be adjusted to between 140 mg and 1.4 g daily according to the response and gastrointestinal tolerance. It should be given not less than 1 hour before or 2 hours after meals.

Preparations

British Pharmacopoeia 2008: Estramustine Phosphate Capsules.

Proprietary Preparations

Argentina: Amsupros †; Estracyt;

Austria; Estracyt;

Belgium: Estracyt;

Canada: Emcyt;

Chile: Estracyt;

Czech Republic: Estracyt;

Denmark: Estracyt;

Finland: Estracyt;

France: Estracyt;

Germany; cellmustin; Estracyt; Medactin; Multosin; Prostamustin †;

Greece: Estracyt;

Hong Kong; Estracyt;

Hungary: Estracyt;

India: X-Trant;

Ireland: Estracyt;

Israel: Estracyt;

Italy: Estracyt;

Japan: Estracyt;

Malaysia: Estracyt †;

Mexico: Emcyt;

The Netherlands: Estracyt;

Norway: Estracyt;

Poland: Estracyt;

Portugal: Estracyt;

Russia: Estracyt;

South Africa: Estracyt;

Singapore: Estracyt;

Spain: Estracyt;

Sweden: Estracyt;

Switzerland: Estracyt;

Turkey: Estracyt;

United Kingdom (UK): Estracyt;

United States of America (USA): Emcyt;

Venezuela: Estracyt.