A comparison study of lipid and androgen metabolism with triphasic oral contraceptive formulations containing norgestimate or levonorgestrel.

Abstract

The effects of norgestimate triphasic (Ortho Tri-Cyclen, Tri-Ciles) and levonorgestrel triphasic (Triphasi) formulations on lipid and androgen metabolism were assessed in a study of 66 healthy women treated through six menstrual cycles. Levels of the following were measured: cholesterol and its subfractions, triglycerides, carrier lipoproteins, estradiol, testosterone, and sex hormone binding globulin (SHBG). Comparison of baseline values with values after 3 and 6 months of treatment indicated that both regimens influenced lipid and androgen metabolism. There was a statistically significant between-regimen difference in levels of high-density lipoprotein, which were favorably increased with norgestimate triphasic but reduced with levonorgestrel triphasic. Related data on SHBG showed that plasma levels of this marker of estrogen/androgen balance were increased significantly more in the norgestimate triphasic group, providing additional evidence of low androgenicity. Both regimens inhibited follicular growth to the same extent, as evidenced by low mean levels of estradiol in all on-therapy cycles; and both decreased free testosterone. Side effects in both groups were minor and characteristic of those observed with low-dose oral contraceptive agents. The results of the study support the reported safety and positive effects of norgestimate on lipid and androgen metabolism, in comparison with a levonorgestrel-containing combined oral contraceptive.