Oral contraceptives hormonal progestogen-only

Hormonal contraceptives, which use oral oestrogen and/or progesterone, such as combined hormonal contraceptives and progestogen-only contraceptives. 

Q10 When choosing an oral contraceptive, a preparation with the lowest oestrogen and progestogen content that can control the cycle is selected. In older women or women with a history of venous thrombosis who require contraception, a progestogen-only preparation may be more suitable than the combined hormonal type, but unfortunately this is not a suitable choice for Shabana s problem. 

Suggestive case histories raised at an early phase the notion of a possible correlation of oral contraceptives with endometrial cancer. Among cases of endometrial cancer there seemed to be an excess of users of oral contraceptives, particularly of the early high-dose estrogen type. With the virtual demise of these early products, the situation seems to have reversed a 1983 study from the Centers for Disease Control (CDC) in Atlanta showed that women who had used fixed combinations for oral contraception at some time in their lives had a relative risk of endometrial cancer of only 0.5 compared with never-users (112). The protective effect occurred only in women who had used oral contraception for at least 12 months, and lasted for at least 10 years after withdrawal. The WHO adopted the same view in 1988 in the light of multinational data (113). As in the case of hormonal replacement therapy, the protective effect seems to be due to the progestogen component. 

The oral contraceptives are of two main types the combined hormonal contraceptives containing both an oestrogen and a progestogen (monophasic, biphasie, triphasie, or sequential), available as tablets or a patch, and the progestogen-only contraceptives, which are available as tablets (sometimes ealled mini pills), parenteral preparations (implants, depot injections) and intrauterine devices. 

Information is limited, but it appears that these retinoids do not usually alter the efficacy of combined oral contraceptives. The one available case suggests that acitretin reduces the efficacy of progestogen-only oral contraceptives. However, note that progesto n-onty oral contraceptives do not reliably suppress ovulation in all cycles, and that this is not considered their primary mechanism of action (see Hormonal contraceptives and Sex hormones , (p.975)). The single report cannot therefore be taken as evidence that acitretin reduces the efficacy of progestogen-only contraceptives. 

Hormonal contraceptives An interaction of warfarin with hormonal contraceptives has been described in a 33-year-old woman [44 ]. While taking warfarin 38.5 mg/week she switched from a monophasic combined oral contraceptive (ethinylestradiol + nor-ethindrone) to an implantable progestogen-only contraceptive (etonogestrel) 19 days later her INR fell to 1.8 and she required an increase in warfarin dose to 60 mg/week. After 10 months she decided to have the implant removed, and 9 days later her INR rose to 6.5. The warfarin dose was reduced to 55.5 mg/week. She then started to use an oral progestogen-only contraceptive (norethindrone) and the effective warfarin dose was 53.5 mg/ week. The authors hypothesized that the predominant mechanism of this interaction was inhibition of CYP1A2 and CYP2C19 by ethinylestradiol. 

In addition to their use as oral contraceptives, oestrogens and progestogen, either in combination or as oestrogens only treatments, have been used as hormone replacement therapy to alleviate the problems associated with the menopause. 

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