Oral contraceptives progestin-only

Progestin-only oral contraceptive formulations consist of a low dose of either norethindrone or norgestrel... 

C. Although progestin-only oral contraceptive formulations are available, the combination of estrogen and progestin is considered the safest and most desirable type. 

McCann MF, Potter LS. Progestin-only oral contraception a comprehensive review. Contraception 1994 50(6 Suppl 1) S1-S195. 

The minipiir containing only a progestin, rather than a combination estrogen-progestin oral contraceptive, was developed because progestin alone... 

Pharmacology Oral contraceptives (OCs) include estrogen-progestin combinations and progestin-only products. 

Oral Contraceptives, Biphasic, Monophasic, Triphasic, Progestin Only (Table VI-4) [Progestin/Hormone] WARNING ... 

There is some delay in the return of fertility after discontinuation of oral contraceptive use. Gonadotropin profiles should be normal 3 months after combination oral contraceptive use is stopped. The incidence of prolonged amenorrhea extending beyond 6 months is 2 to 3%. This reaction is especially a problem with the use of progestin-only minipills. 

A low dosage of progestin ( mini-pill ) is used, in the form of medroxyprogesterone acetate, which is active at a very low dose. The mini-pill does not inhibit ovulation, but rather interferes with the endometrium and the cervical mucus. The use of this pill prevents most of the side effects of oral contraception, specifically nausea, water retention, and in some cases thrombophlebitis. However, a lower success rate and other frequent side effects have reduced the widespread acceptance of this preparation. Nevertheless, the mini-pill has a role to play in certain specific situations. For example, in an uncommon form of epilepsy called catamenial epilepsy, female patients will experience seizures at particular times during their menstrual cycle, reflecting the fact that seizure focus is stimulated by estrogens but inhibited by progestins. In such women, the mini-pill may afford not only birth control but also improved seizure control. 

Only one implantable contraceptive preparation is available at present. Norgestrel, also utilized as the progestin component of some oral contraceptive preparations, is an effective suppressant of ovulation when it is released from subcutaneous implants. Intramuscular injection of large doses of medroxyprogesterone also provides contraceptive action of long duration. 

Reduction of (r.yS-unsaturated ketones results in reduction not only of the ketone group but of the carbon-carbon double bond as well. Steroidal drugs often fall into this class, including norethindrone. a synthetic progestin found in many oral contraceptive drug combinations. In women, the major plasma and urinary metabolite of norethindrone is the 3jS,Sy3-tetrahydro derivative. ... 

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