Metformin versus sibutramine in the treatment of hyperinsulinemia in chronically anovulating women.

Aim of this study was to compare the effects of metformin and a body weight reduction regimen using sibutramine on insulinemia, insulin sensitivity, and ovarian function in women with anovulatory cycles or infertility. 30 women with anovulatory cycles and hyperinsulinemia were treated with metformin and 15 anovulating women with obesity were treated with sibutramine in combination with a caloric restriction diet and physical exercise. In the metformin group there was a mild decrease of the body mass index (BMI), a decrease of fasting and stimulated insulinemia (I0, p < 0.05, I120, p < 0.01), a significant reduction of insulin resistance calculated as index FIRI (p < 0.05), serum LH (p < 0.05) and testosterone levels (p < 0.05). There was an improvement of menstrual cycles in 21 (70 %) of women, and 6 of them became pregnant. In the sibutramine group we found a significant decrease of BMI (p < 0.01), waist circumference (p < 0.01), fasting and stimulated insulinemia (p < 0.05, p < 0.01) and a significant improvement of insulin sensitivity (FIRI, p < 0.01). However, the levels of FSH, LH, and testosterone were not significantly changed. There was a significantly greater reduction of insulin levels and FIRI after sibutramine treatment compared with metformin treatment, while the changes of LH were not signifcantly different. Testosterone was changed more after metformin therapy. We conclude that although the body weight reduction using sibutramine has a more pronounced effect on insulinemia and insulin sensitivity, metformin may be more effective in the prompt restoration of ovarian function. (Tab. 3, Ref. 24.).