Oral contraceptives come in various formulations. The main division is between combined oral contraceptive pills, containing both estrogen and progestogen (progestin) progestogens, and progestogen-only pills. Combined oral contraceptive pills also come in a variety of types, including various doses of estrogen, and whether the dose of estrogen or progestogen changes from week to week.
Video Birth control pill formulations
Action mechanism
Combination pills usually work by preventing ovaries from releasing eggs (ovulation). They also thicken cervical mucus, which makes sperm do not enter the uterus and join the egg. Hormones in combination pills and progestogens alone also dilute the lining of the uterus. This can prevent pregnancy by impairing blastocyst implantation.
The main action commonly used is the prevention of ovulation.
Maps Birth control pill formulations
combined oral contraceptive pills
All contain estrogen, ethinylestradiol or mestranol, in varying amounts, and one of a number of different progestogen. (Regarding estrogens, 3-methyl ether ethinylestradiol inactivated, which must be metabolized by the liver to active ethinylestradiol; 50 Ã,Âμg mestranol is equivalent to only 35 μg ethinylestradiol and should not be used when high doses [50 Ã,Âμg etinilestradiol] estrogen pills required; mestranol is the estrogen used in the first oral contraceptive, Enovid). They are usually taken for 21 days with then seven days gap during blood withdrawal (often, but incorrectly, referred to as menstrual periods) occur. It differs in the amount of estrogen administered, and whether they are monophasic (same estrogen and progestogen dose for 21 days each) or multiphasic (dose varies). The introduction of the extended-cycle monophasic pill (ie Seasonale) has shown that the interval of withdrawal of blood can be reduced.
Monophasic
- 3/2/1 mg estradiol valerate: estrophasic
- estradiol valerate/combination dienogest with 2 tablets 3 mg/0 mg, followed by 5 tablets 2 mg/2 mg, 17 tablets 2 mg/3 mg, 2 tablets 1 mg/0 mg and 2 placebo. (AU, EU, RU: Qlaira, USA: Natazia, Bayer)
Progestogen Pill only
Progestogen only pills (POPs) use only progestogens with continuously taken doses and no gaps between packages are taken. People who use it may experience irregular bleeding, and while irregular in the first few months of taking, usually settle on a regular pattern in time.
The following progestogen is used:
- 350 Ã,Âμg norethisterone (norethindrone) (English: Micronor, Janssen-Cilag; Noriday, Pfizer; AS: Micronor, Ortho-McNeil; Nor-QD, Watson; Nora-BE; Watson; Jolivette, Watson ; Camila, Barr; Errin, Barr; Heather, Glenmark; RU: Primolut-Nor, Bayer; Norkolut, Richter Gedeon)
- 500Ã,Âμg etynodiol diacetate (English: Femulen, Pfizer)
- 30Ã,Âμg levonorgestrel (UK: Norgeston, Bayer; AUS, RU: Microlut, Bayer)
- 75Ã,Âμg desogestrel (English: Cerazette, Loestrin; RU: Cerazette, Organon; Lactinette, Richter Gedeon; SE: Gestrina)
- 500Ã,Âμg lynestrenol (RU: Exluton, Organon)
Contraindications
Oral contraceptives generally should not be used in people who currently have the following conditions:
- Thrombophlebitis or thromboembolic disorder
- Historical history of thrombophlebitis or deep vein thromboembolism
- Cerebrovascular or coronary artery disease (current or history)
- Valvular heart disease with thrombogenic complications
- Severe hypertension
- Diabetes with vascular involvement
- Headache with focal neurological symptoms
- Large operation with prolonged immobilization
- Known or suspected breast carcinoma or personal history of breast cancer
- Endometrial carcinoma or estrogen-dependent or suspected estrogen neoplasia
- Undiagnosed undiagnosed genital hemorrhage
- jaundice cholestatic jaundice or jaundice with previous pill use
- Hepatic adenoma or carcinoma, or active liver disease
- Known or suspected pregnancies
- Hypersensitivity to any component of the product
More comprehensive guidelines covering risk and benefit analysis can be found in the World Health Organization's Medical Eligibility for Contraceptive Use Guidelines as reflected in CDC Medical Feasibility for Guidelines for Contraceptive Use.
See also
- Mestranol/noretynodrel (Enovid) - the first oral contraceptive
- List of progestogen available in the United States
- List of estrogens available in the United States
References
Source of the article : Wikipedia
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