Metformin Dose, Tolerability and Factors Influencing Clinical Response to Metformin Therapy in Patients with Polycystic Ovarian Syndrome

Objectives: To investigate the tolerability to different doses of metformin and the effect of the Body Mass Index (BMI), hormonal profile, insulin glucose ratio and metformin dose and duration of therapy on the clinical outcome in patients with polycystic ovarian syndrome (PCOS). Study Design: Retrospective analysis. Patients and Methods: Data from 76 consecutive patients with PCOS who received metformin between 2001 and 2003 attending the infertility and Gynaecology clinics at Sheffield Teaching Hospitals. Results: Side effects occurred in 26 patients (21%), out of these 18 patients (56 %), had side effects severe enough to cause discontinuation of treatment. The duration of metformin therapy was significantly longer in responders compared to non responders (7.4±5.4 months in responders Vs 6.2±5 months in non responders, p 0.05). There was no evidence for a significant difference in other clinical factors between the two groups (BMI, endocrine profile, ovarian volume or dose of metformin). Conclusion: The only factor that has a likely impact on the response to metformin is the duration of metformin therapy. Metformin therapy can be associated with poor compliance due to side effects. Stopping then gradually increasing the dose may result in better compliance.