Oestrogens contraceptives

Conjugated oestrogens (see also Steroidal oestrogens) Contraceptives, oral (see Combined oral contraceptives ... 

DANAZOL OESTROGENS L efficacy of both danazol and oestrogen contraceptives Uncertain possibly competition for same receptors Use alternative forms of contraception... 

Drugs with endocrinological functions or side-effects are common, but oestrogenic hormones in oral contraceptives are particularly widely used. Pharmaceuticals and their metabolites eventually find their way into the environment, predominantly via excretion into sewage. ... 

Since the development of the oral contraceptive steroids in the 1960s, various steroids and procedures have been used. Synthetic steroids are now used since their half-hves in the body are longer than the natural steroids. Combined oestrogen-progesterone contraception involves taking one piU each day which contains a synthetic progestogen plus an oestrogen. The pill is taken for 21 dyas, with a break for... 

Levonorgestrel is a progestogen derivative. It is found either in combined oral contraceptives coupled with an oestrogen derivative or alone in progestogen-only contraceptives. 

Q64 Initiating carbamazepine therapy in a patient receiving oral contraceptives decreases the contraceptive effect. Carbamazepine decreases the metabolism of oestrogens and progestogens. 

Corbamazepine interacts with oral contraceptives. Corbamazepine increases the metabolism of oestrogens and progestogens resulting in a decrease in the plasma concentration of oestrogens and progestogens. This in turn brings about a decrease in the contraceptive level provided. 

Thus, the natural oestrogen estrone can be converted into the drug ethinylestradiol by nucleophilic addition. Ethinylestradiol is some 12 times more effective than estradiol when taken orally, and is widely used in oral contraceptive preparations. In drug nomenclature, the systematic name ethynyl- for the HC=C- group is usually presented as ethinyl-. 

The major oestrogen preparations used medically are outlined in Table 1.12, and their chemical structure is illustrated in Figure 1.3. The widest clinical application of oestrogens relate to their use as oral contraceptives. Most such contraceptive pills contain an oestrogen in combination with a progestin (discussed later). 

Ethinyloestradiol Synthetic oestrogen Used for oestrogen replacement therapy in deficient states, both pre- and postmenopausal. Treatment of prostate cancer (male), breast cancer (post-menopausal women). Component of many oral contraceptives... 

Mestranol Synthetic oestrogen Treatment of menopausal, post-menopausal or menstrual disorders. Component of many oral contraceptives... 

In some well-documented cases given oral antibiotics, contraception has failed - presumably because gut bacteria have been killed and the recycled component of oestrogen lost with a consequent fall in plasma oestrogen. It is possible to be pregnant on the pill in this case ... 

Combined oral contraceptives (see Oral contraceptives, combined) Conjugated equine oestrogens... 

Sequential oral contraceptives (see also Oestrogens, progestins and eombinations)... 

Bruni V, Rosati D, Bucciantini S, Verni A, Abbate R, Pinto S, Costanzo G, Costanzo M. Platelet and coagulation functions during triphasic oestrogen-progestogen treatment. Contraception 1986 33(l) 39-46. 

Ylikorkala O, Puolakka J, Viinikka L. Oestrogen containing oral contraceptives decrease prostacyclin production. Lancet 1981 1(8210) 42. 

Bottiger LE, Boman G, Eklund G, Westerholm B. Oral contraceptives and thromboembolic disease effects of lowering oestrogen content. Lancet 1980 1(8178) 1097-101. 

Scragg RK, McMichael AJ, Seamark RF. Oral contraceptives, pregnancy, and endogenous oestrogen in gall stone disease—a case-control study. BMJ (Clin Res Ed) 1984 288(6433) 1795-9. 

World Health Organization Collaborative Study of Cardiovascular Disease and Steroid Hormone Contraception. Effect of different progestagens in low oestrogen oral contraceptives on venous thromboembolic disease. Lancet 1995 346(8990) 1582-8. 

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