Sizing up insulin resistance—one treatment doesn’t fit all
There is no single best intervention for all women. It depends on the severity of glucose intolerance and metabolic abnormality in each patient.
Higher doses may be more effective. Although the Diabetes Prevention Program study recommends a metformin dose of 850 mg twice a day, I prefer 2,000 mg a day in 2 divided doses. A dose-ranging study for type 2 diabetes found this to be the most effective dose for improving glycemic parameters.18 I use a step-up regimen of 500-mg doses over 5 to 7 days until the 2,000-mg dose is attained, and will plateau the patient at a lower dosage if she does not tolerate the higher amount, most commonly due to gastrointestinal side effects.
Monitor at least annually
This patient warrants visits at least yearly to monitor her condition. The visits should include a lipid profile and, every few years, an OGTT. A glycosylated hemoglobin in lieu of the OGTT may be another option.
It also is prudent to monitor renal function at baseline and at least annually, given the renal clearance of metformin.
In addition, I would continue the OC, as there are no known interactions between OCs and metformin, and at least 1 randomized study19 suggests the combination of the 2 is metabolically superior to an OC alone.
Scant evidence suggests that metformin alone improves hirsutism or results in eumenorrhea, and there are no data on endometrial cancer protection.
Dr. Legro has received grant support from Pfizer and served as a consultant for Ortho-McNeil and Abbott Laboratories.
