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Premarin (Conjugated Oestrogens)

Last updated on May 31, 2023
Conjugated OestrogensSynonyms: Conjugated Estrogens; Conjugated Oestrogens; Estrógenos conjugados; Estrogeenit, konjugoidut; Estrogena Coniugata; Estrogenai, konjuguoti; Estrogener, konjugerade; Estrogeni Coniunct; Estrogeni Coniuncti; Estrogeny konjugované; Konjugált ösztrogének
ATC code: G03CA57
Read code: y02ar; y08DY [Endocrine Use]

Pharmacopoeias. In Europe and US.

European Pharmacopoeia, 6th ed. (Estrogens, Conjugated). A mixture of various conjugated forms of oestrogens obtained from the urine of pregnant mares or by synthesis, dispersed in a suitable powdered diluent. It contains two principal components, 52.5 to 61.5% of sodium estrone sulfate and 22.5 to 30.5% of sodium equilin sulfate the total of the combined two is 79.5 to 88.0%. It also contains 2.5 to 9.5% of sodium 17a-estradiol sulfate, 13.5 to 19.5% of sodium 17a-dihydroequilin sulfate, and 0.5 to 4.0% of sodium 17p-dihy-droequilin sulfate. All percentages are related to the labelled content.

An almost white brownish amorphous powder.

The United States Pharmacopeia 31, 2008 (Conjugated Estrogens). A mixture of sodium estrone sulfate and sodium equilin sulfate, derived wholly or in part from equine urine or synthetically from estrone and equilin. It contains other conjugated oestrogenic substances of the type excreted by pregnant mares. It contains 52.5 to 61.5% of sodium estrone sulfate and 22.5 to 30.5% of sodium equilin sulfate the total of the two combined should comprise 79.5 to 88.0% of the labelled content of conjugated oestrogens.

It should contain, as sulfate conjugates, 13.5 to 19.5% of 17a-dihydroequilin, 2.5 to 9.5% of 17a-estradiol, and 0.5 to 4.0% of 17p-dihydroequilin, relative to the labelled content of conjugated oestrogens. If it is obtained from natural sources it is a buff-coloured amorphous powder which is odourless or has a slight characteristic odour the synthetic form is a white to light buff-coloured crystalline or amorphous powder, odourless or with a slight odour. Store at a temperature of 25°, excursions permitted between 15° and 30°.

Synthetic Conjugated Estrogens, A

Synthetic Conjugated Oestrogens, A.

Синтетические Конъюгированные Эстрогены, A

Synthetic Conjugated Estrogens, B

(US Adopted Name)

CE-10 Synthetic Conjugated Oestrogens, B.

Синтетические Конъюгированные Эстрогены, B.

CAS 746658-13-9.

Adverse Effects and Precautions

As for oestrogens in general (see Estradiol). See also under Hormone Replacement Therapy.

Effects on the cardiovascular system

In an early study of men with a previous myocardial infarction, treatment with conjugated oestrogens 5 mg daily was stopped because of a higher incidence of subsequent coronary events. Moreover, treatment with the lower 2.5 mg dose was later also stopped because of suggestions of adverse trends including a greater incidence of venous thromboembolism.

For the cardiovascular effects of HRT, including conjugated oestrogens, in women.

Effects on the nervous system

Reversible chorea has been described in 2 women given conjugated oestrogens with a progestogen as postmenopausal HRT in 1 case the patient had a history of migraine and Sydenham’s chorea. Chorea also recurred in a postmenopausal woman with a history of chorea gravidarum when she was given vaginal conjugated oestrogens.

Hypersensitivity. An anaphylactic reaction after intravenous conjugated oestrogens has been reported.


See under Hormone Replacement Therapy.


Conjugated oestrogens taken orally are hydrolysed by enzymes present in the intestine that remove the sulfate group and allow absorption of the unconjugated oestrogen. Metabolism occurs primarily in the liver there is some enterohepatic recycling (see also under Estradiol).

Uses and Administration

premarinConjugated oestrogens have actions and uses similar to those described for estradiol. When used as menopausal HRT doses of 0.3 to 1.25 mg daily are given orally either cyclically or continuously, with a progestogen either cyclically or continuously in women with a uterus. Doses of 0.3 to 1.25 mg may also be used for the prevention of postmenopausal osteoporosis, but oestrogen therapy is generally reserved for women who are at significant risk and who cannot be given non-hormonal treatment.

Topical vaginal therapy may be used specifically for menopausal atrophic vaginitis, atrophic urethritis, and kraurosis vulvae 0.5 to 2 g of a 0.0625% cream may be used daily for 3 weeks of a 4-week cycle. For women with a uterus, the addition of cyclical progestogen is generally not required during topical vaginal oestrogen therapy. However, the use of a progestogen may be considered, and during long-term therapy these women should be monitored for evidence of endometrial hyperplasia.

When given as replacement therapy on a cyclical basis, oral doses of 1.25 mg daily are used for primary ovarian failure, adjusted according to response. Doses of 300 to 625 micrograms daily are usually given for female hypogonadism, although higher doses were formerly used.

For the palliative treatment of prostatic carcinoma, an oral dose of 1.25 to 2.5 mg three times daily has been used. A dose of 10 mg three times daily for at least 3 months has been used for palliative treatment of breast carcinoma in men and postmenopausal women.

Abnormal uterine bleeding has been treated acutely by giving 25 mg of conjugated oestrogens by slow intravenous injection, repeated if required after 6 to 12 hours the intramuscular route has also been used. Synthetic conjugated oestrogens are derived from plant material, and are not a generic equivalent of Conjugated Estrogens described in the United States Pharmacopeia 31, 2008 (see above). Synthetic conjugated estrogens, A, contains a mixture of nine derivatives of estrone, equilin, estradiol, and equilenin. It is used in oral doses of 0.45 to 1.25 mg daily for the relief of vasomotor symptoms associated with the menopause.

A dose of 300 micrograms daily may be used for menopausal vulvar and vaginal atrophy, but an alternative topical therapy should be considered if this is the only symptom being treated. Synthetic conjugated estrogens, B, contains a mixture of ten derivatives of estrone, equilin, estradiol, and equilenin. It is used in oral doses of 0.3 to 1.25 mg daily for the relief of vasomotor symptoms associated with the menopause. A dose of 300 micrograms daily may be used for menopausal vulvar and vaginal atrophy, but an alternative topical therapy should be considered if this is the only symptom being treated.

Administration in children

Conjugated oestrogens have been used to reduce final height in girls with constitutional tall stature (see Growth Disorders, under Estradiol). They have also been used in children for some haemorrhagic disorders (below).

Haemorrhagic disorders

Case reports and small studies have described the use of high-dose conjugated oestrogens in the management of haemorrhagic disorders associated with renal failure, although it is unclear how oestrogens might reduce prolonged bleeding times in these patients. Treatment has been given orally, but an intravenous dose of 600 micrograms/kg given over 30 to 40 minutes, once daily for 5 days, has been reported most often.

Conjugated oestrogens have also been used in various doses in the management of haemorrhagic cystitis, particularly that caused by high-dose cyclophosphamide therapy. The successful use of 25 mg intravenously for 2 consecutive days has been reported, as has a regimen consisting of a 1 mg/kg intravenous dose followed by 5 mg orally for 3 weeks. A report of treatment in 10 patients described the use of oral conjugated oestrogens in doses of 6 to 12 mg daily, usually in three divided doses, for durations of 5 days to 16 weeks. Another report of therapy in 10 children aged between 8 and 19 years described intravenous doses of 12.5 to 50 mg twice daily, often for 2 or 3 days, followed by oral doses ranging from 2.5 mg twice daily to 5 mg four times daily for durations of a few days to about 3 weeks.

Oestrogens have also been used in the treatment of other bleeding disorders (see Estradiol).


The United States Pharmacopeia 31, 2008: Conjugated Estrogens Tablets.

Proprietary Preparations

Argentina: Belestar Livomarin Premarin

Australia:: Premarin

Austria: Conjugen Oestro-Feminal Premarin

Belgium: Premarin

Brazil: Estrogenon Estroplus Gestrocon Menoprin Menosedan Prem Premarin Repogen

Canada: CES Congest Premarin

Chile: Climatrol E Conpremin Estrarona Profemina

Czech Republic: Oestrofeminal Premarin Presomen

Denmark: Premarin

Finland: Premarin

France: Premarin

Germany: Climarest Climopax mono Femavit Oestrofeminal Presomen Transannon

Greece: Premarin

Hong Kong: Equin Premarin

Hungary: Premarinf

India: Espauz Estrin Premarin

Israel: Premaril Prevagin-Premaril

Italy: Emopremarinl Premarin

Malaysia: Premarin

Mexico: Equifan Fahifem Neradin Premarin Six Din Sultrona Terapova

The Netherlands: Dagynil Premarin PremarinLite

New Zealand: Premarin

Philippines: Menpoz Premarin

South Africa: Premarin

Singapore Equin Premarin

Spain: Equin Longaplex Premarin

Sweden: Premarina

Switzerland: Premarin Transannon

Thailand: Estromon Premarin

Turkey: Premarin

UK: Premarin

USA: Cenestin Enjuvia Premarin

Venezuela: Biostrogen Climatrol E Menostat Premarin.


The symbol ¤ denotes a preparation which is discontinued or no longer actively marketed.

Argentina: Periofem Ciclico¤; Periofem Continuo¤; Premelle Ciclico; Premelle Continuo;
Australia: Menoprem¤; Premia Continuous; Premia Low; Premia; Provelle¤;
Austria: Cyclo-Premarin-MPA¤; Cyclo-Premella¤; Perennia; Premarin compositum; Premarin MPA¤; Premarin Plus; Premella¤; Sequennia;
Belgium: Premelle Cycle; Premelle; Premplus¤;
Brazil: Ero Test¤; Menosedan Ciclo; Menosedan Fase; Menosedan MPA; Menostress¤; Menotensil; Premarin MPA¤; Premelle Ciclo; Premelle; Prempro Bifasico; Prempro Monofasico; Repogen Ciclo; Repogen Conti; Selecta;
Canada: Premarin with Methyltestosterone¤; Premplus;
Chile: Climatrol Continuo; Climatrol HT Continuo; Climatrol HT; Conpremin Pak Plus; Conpremin Pak; Novafac 30; Novafac CC; Novafac; Prempak; Profemina CC; Profemina MP;
Czech Republic: Cyclo-Premella; Premella; Presomen Compositum;
Germany: Climopax Cyclo; Climopax; Ovaribran¤; Presomen Compositum; Seda-Presomen¤; Transannon comp.¤; Transannon Plus¤;
Greece: Premelle Cycle; Premelle;
Hong Kong: Premelle Cycle; Premelle; Prempak¤;
Hungary: Cyclo-Premella; Premella;
Ireland: Premique Cycle; Premique; Prempak-C;
Israel: Premaril MP; Premaril Plus MP;
Italy: Premelle Combinato; Premelle S¤; Premelle Sequenziale; Prempak;
Malaysia: Plentiva Cycle 5; Plentiva; Premelle; Prempak;
Mexico: Premarin Pak¤; Premelle;
Netherlands: Premarin Plus; Premelle Cycle; Premelle; PremelleLite; Prempak-C;
New Zealand: Menoprem; Premia Continuous; Premia; Prempak-C¤; Provette Continuous¤; Provette Sequential¤;
Portugal: Premarin Plus; Premelle Cycle; Premelle;
South Africa: PMB¤; Premelle; Prempak N;
Singapore: Premelle Cycle; Premelle; Prempak-C; Spain: Premelle Ciclico; Premelle;
Sweden: Premelle Sekvens; Premelle; Switzerland: Cyclo-Premella ST; Cyclo-Premella¤; Premarin Plus; Premella; Premia;
Thailand: Premelle Cycle; Premelle; Prempak¤;
United Kingdom: Premique Cycle; Premique; Prempak-C;
United States: Mediatric¤; PMB¤; Premarin with Methyltestosterone¤; Premphase; Prempro;
Venezuela: Climatrol HT Ciclico; Climatrol HT Continuo; Cyclogesterin; Premelle Ciclico; Premelle Continuo; Premelle Plus Continuo

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