The New Option in Low-Dose Oral Contraception [antikvár]

THE NEW OPTION IN LOW-DOSE ORAL CONTRACEPTION INTRODUCTION Since their introduction over 30 years ago, oral contraceptives have evolved in a number of ways. Prompted by the discovery that the use of oral contraceptives with a high estrogen dose was associated with an increased incidence of cardiovascular disease', there has been a progressive reduction in the dose of this steroid. Whilst the first oral contraceptives to be introduced contained either 150 ng mestranol or 100(ig ethinylestradiol, most preparations used today contain between 20 and 35|lg of ethinylestradiol. Epidemiological studies suggest that this approach has been successful, and there has been a parallel decrease in the risk of both deep vein thromboembohc disease- and cerebral thrombosis^. As well as a progressive reduction in estrogen dose, new progestogens have been developed, and the dose of this component has also been reduced. The so-called 'third-generation' progestogens, gestodene, desogestrel and norgesti-mate, appear to be associated with better cycle control and may offer benefits in terms of improved tolerability. The development of phasic dosage regimes has also assisted in reducing the total progestogen dose. The latest development in the evolution of combined oral contraceptives has been the combination of a 20 Hg ethinylestradiol dose with a third-generation progestogen, in a monophasic regimen. The first such formulation to be introduced combined 20|Ig ethinylestradiol with 150|Ig desogestrel and, more recently, a formulation utilizing the progestogen gestodene has been introduced. Despite the confidence of the pharmaceutical industry, responsible chnicians wiU wish to scrutinize the advantages of such preparations and think carefully about whether some of the great benefits of higher-dose combined oral contraceptives might be lost. This is, after all, the approach which must be taken to any new advance in medicine. This paper, therefore, examines the logic behind the use of20pg ethinylestradiol pills and the development ofa preparation containing 75 |xg gestodene.