The concern regarding oral contraceptives and antibiotics is essentially theoretical, owing to the action of broad-spectrum antibiotics, which reduce the gut flora bac- teria and thus may result in decreased absorption of estrogen. This could lead to a possible reduction in the efficacy of oral contraceptives, although pharmacokinetic studies suggest that serum levels of estrogen are unaffected by antibiotics such as tetracycline, doxycycline, and others (52,53). Nevertheless, there have been very few reports in the literature of pregnancies associated with the use of antibiotics
in conjunction with oral contraceptives (54,55). Existing reports have focused on tetracycline, and the incidence was 1.2 to 1.4 pregnancies/100 woman years of use of the oral contraceptive. These data are no greater than the background failure rate of oral contraceptives (54,55).
NEWER FORMS OF CONTRACEPTIVES
Recently, newer forms of contraceptives have been developed, such as contracep- tive patches, vaginal rings, and injectable combination hormones. Each of these is designed to suppress ovulation and in this regard will lower the ovarian production of androgens. As of yet, these formulations have not been studied in the treatment of acne. The contraceptive patch (Ortho Evra) contains 20 mg of ethinyl estradiol and 150 mg of the progestin, norelgestromin. The patch is worn for three weeks and removed for one week, during which time menstrual bleeding will occur. The advantages of this formulation are better patient compliance, dosing that is not affected by gastrointestinal disturbances, and more consistent serum levels of estrogen serum levels compared to oral dosing (56). The vaginal ring (NuvaRing) is a contraceptive vaginal ring that releases 15 mg of ethinyl estradiol and 120 mg of the progestin, etonogestrel. It is placed within the vagina for three weeks and removed for one week. In one study, the incidence of irregular bleeding was less compared with an oral combination contraceptive (57). An injectable combination of estradiol cypionate and medroxyprogesterone acetate (Lunelle) has been devel- oped. This is given as a monthly contraceptive injection. Contraceptive efficacy was shown to be comparable to a triphasic oral contraceptive containing ethinyl estra- diol and norethindrone (Ortho 7/7/7) (58).
APPROACH TO HORMONAL THERAPY IN FEMALE ACNE
Hormonal therapy is an excellent option for treatment of women whose acne is not responding to conventional therapy. If there are signs of hyperandrogenism, an endocrine evaluation is indicated, consisting of tests such as DHEAS, total- and free-testosterone, and an LH/FSH ratio. Although hyperandrogenism is an indi- cation for hormonal therapy, women with normal serum androgen levels also respond well to treatment. The mainstays of hormonal therapy include oral contra- ceptives and spironolactone. Other agents to choose from include cyproterone acetate, flutamide, and glucocorticoids. Hormonal agents work best as part of a combination regimen including topical retinoids or topical or oral antibiotics depending upon the severity of the acne. In some women, the additional of hormo- nal therapy has improved acne to the point where subsequent treatment with iso- tretinoin was no longer necessary. As more is learned about the hormones involved in acne, their source of production and the mechanisms by which they influence sebaceous gland growth and sebum production, new opportunities will arise for the development of novel therapies aimed at the hormonal aspects of acne.