Efficacy and safety of a monophasic and a triphasic oral contraceptive containing norgestimate

Abstract

Both monophasic and triphasic formulations of ethinyl estradiol plus norgestimate, a progestin with marked progesterone-receptor affinity and minimal androgen-receptor affinity, have been evaluated in numerous clinical studies designed to determine if norgestimate's receptor-binding profile provides enhanced safety without a reduction in efficacy. To date clinical trials have shown that both formulations of ethinyl estradiol/norgestimate offer contraceptive efficacy equivalent to that of other oral contraceptives. Monophasic ethinyl estradiol/norgestimate was associated with an incidence of breakthrough bleeding and spotting similar to that of monophasic ethinyl estradiol/norgestrel and an incidence of amenorrhea less than that of ethinyl estradiol/norgestrel. Cycle control with triphasic ethinyl estradiol/norgestimate was similar to that with monophasic ethinyl estradiol/norgestimate. Weight gain and elevated blood pressure were insignificant in clinical trials with both fixed-dose and phasic ethinyl estradiol/norgestimate formulations. Perhaps of greatest importance, both monophasic and triphasic ethinyl estradiol/norgestimate formulations consistently showed favorable impact on metabolic parameters, including elevations in serum high-density lipoprotein cholesterol, and reductions in the low-density lipoprotein/high-density lipoprotein ratio, the parameter considered most sensitive for atherosclerotic risk. Both monophasic and triphasic ethinyl estradiol/norgestimate formulations were associated with minimal and clinically neutral effects on carbohydrate metabolism.