Insulin-lowering medications in polycystic ovary syndrome

A growing body of evidence suggests that serum hyperinsulinemia contributes to the excess ovarian androgen secretion observed in women with PCOS. As a group, women with PCOS are hyperinsulinemic and insulin resistant when compared with weight-matched normal women, but not all PCOS subjects display clear metabolic defects. The small studies using insulin-sensitizing drugs have demonstrated conclusively that a reduction in serum insulin levels is associated with a reduction of ovarian androgen secretion in PCOS, providing further evidence that hyperinsulinemia contributes to hyperandrogenism by increasing ovarian androgen secretion and reducing SHBG. The improvement of serum androgen levels with multiple different drug classes with different mechanisms of actions suggests an effect mediated by reduction in circulating insulin levels rather than a direct ovarian effect of the drugs. Although the studies published to date have increased understanding of the pathophysiologic mechanisms of PCOS, before these drugs can be recommended as first-line therapy for women, longer term clinical trials are needed to compare their safety and efficacy with other established therapies, such as oral contraceptive pills and antiandrogens. Because of the potential direct and unique beneficial effects of these medications on metabolism, studies must be performed to evaluate their efficacy in combination with other therapies, especially oral contraceptives. It is likely that subsets of patients who cannot tolerate traditional medications will be better managed with insulin sensitizers as first-line therapy; however, to date, the optimal way to identify these subjects is unknown. Whether therapy should be limited to subjects with documented hyperinsulinemia also remains unknown.