Aspen Surgical

CYCLESSA

desogestrel; ethinyl estradiol

LOE Approaching

ORAL-28 · TABLET

CLINICAL PHARMACOLOGY Pharmacodynamics Combined oral contraceptives act by suppression of gonadotropins. Although the primary mechanism of this action is inhibition of ovulation, other alterations include changes in the cervical mucus, which increase the difficulty of sperm entry into the uterus, and changes in the endometrium which reduce the likelihood of implantation. Receptor binding studies, as well as studies in animals, have shown that 3-keto-desogestrel, the biologically active metabolite of desogestrel, combines high progestational activity with minimal intrinsic androgenicity . The relevance of this latter finding in humans is unknown. Pharmacokinetics Desogestrel is rapidly and almost completely absorbed and converted into 3-keto-desogestrel, its biologically active metabolite. Following oral administration, the relative bioavailability of desogestrel, as measured by serum levels of 3-keto-desogestrel, is approximately 84%. In the third cycle of use after a single dose of desogestrel and ethinyl estradiol tablets 0.15 mg/0.03 mg, maximum concentrations of 3-keto-desogestrel of 2,805 ± 1,203 pg/mL (mean ± SD) are reached at 1.4 ± 0.8 hours. The area under the curve (AUC 0–∞ ) is 33,858 ± 11,043 pg/mL∙hr after a single dose. At steady state, attained from at least day 19 onwards, maximum concentrations of 5,840 ± 1,667 pg/mL are reached at 1.4 ± 0.9 hours. The minimum plasma levels of 3-keto-desogestrel at steady state are 1,400 ± 560 pg/mL. The AUC 0–24 at steady state is 52,299 ± 17,878 pg/mL∙hr. The mean AUC 0–∞ for 3-keto-desogestrel at single dose is significantly lower than the mean AUC 0–24 at steady state. This indicates that the kinetics of 3-keto-desogestrel are non-linear due to an increase in binding of 3-keto-desogestrel to sex hormone-binding globulin in the cycle, attributed to increased sex hormone-binding globulin levels which are induced by the daily administration of ethinyl estradiol. Sex hormone-binding globulin levels increased significantly in the third treatment cycle from day 1 (150 ± 64 nmol/L) to day 21 (230 ± 59 nmol/L). The elimination half-life for 3-keto-desogestrel is approximately 38 ± 20 hours at steady state. In addition to 3-keto-desogestrel, other phase I metabolites are 3α-OH-desogestrel, 3β-OH-desogestrel, and 3α-OH-5α-H-desogestrel. These other metabolites are not known to have any pharmacologic effects, and are further converted in part by conjugation (phase II metabolism) into polar metabolites, mainly sulfates and glucuronides. Ethinyl estradiol is rapidly and almost completely absorbed. In the third cycle of use after a single dose of desogestrel and ethinyl estradiol tablets, the relative bioavailability is approximately 83%. In the third cycle of use after a single dose of desogestrel and ethinyl estradiol tablets, maximum concentrations of ethinyl estradiol of 95 ± 34 pg/mL are reached at 1.5 ± 0.8 hours. The AUC 0–∞ is 1,471 ± 268 pg/mL∙hr after a single dose. At steady state, attained from

2000

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