Context: Weight loss and metformin therapy are beneficial in improving the hormonal and metabolic consequences of PCOS. Rimonabant has been found to reduce weight and improve the metabolic profile in patients with metabolic syndrome.
Objective: To compare the effects of metformin and rimonabant on insulin resistance and biochemical hyperandrogenemia.
Subjects: Twenty patients with PCOS and biochemical hyperandrogenemia were recruited to a randomised, open labelled parallel study.
Intervention: Patients were randomised to 1.5 g daily of metformin or 20 mg daily of rimonabant.
Main outcome measures: The primary end points of the study were change in total testosterone.
Results: After 12 weeks of rimonabant there was a significant reduction (Mean±S.E.M.) in weight (104.6±4.6 vs 98.4±4.7 kg, P<0.01), waist circumference (116.0±3.3 vs 109.2±3.7 cm, P<0.01), hip circumference (128.5±4.0 vs 124.1±4.2 cm, P<0.03), waist hip ratio (0.90±0.02 vs 0.88±0.01 P<0.01) free androgen index (FAI) (26.6±6.1 vs 16.6±4.1 P<0.01) and testosterone (4.6±0.4 vs 3.1±0.3 nmol/l (132.7±11.5 vs 89.4±8.65 ng/dl) P<0.01), and insulin resistance (HOMA-IR) (4.4±0.5 vs 3.4±0.4 P<0.05). There was no change in any of these parameters in the metformin treated group.
Conclusion: Rimonabant improves anthropometric parameters, biochemical hyperandrogenemia as well as insulin resistance in patients with PCOS and is superior to metformin in reducing weight and serum testosterone concentration over a short term 12 weeks period.