:
Some women with insulin resistance respond to metformin therapy, which improves insulin resistance and aids weight loss. There is a lack of large-scale, properly conducted clinical trials on this drug, but the best information to date suggests that metformin (at a dose of 1.5-2g daily) restores ovulation in around 50 per cent of women with PCOS who are not ovulating.
and the other quote from my friend's email:
:
As you know by now, the recommended dose for ovulation stimulation is 1500 to 2550 mg per day. In non-obese women with PCOS the dose used in the studies was 850 mg twice daily. The evidence shows similar rates of ovulation with metformin or with clomid (note that these are only about 67%) but that pregnancy rates are higher with metformin. So for that reason alone I would keep taking it as it increases the chance that pregnancy will follow if you manage to get ovulation to occur. There is also a lower rate of spontaneous miscarriage with metformin. They recommend the following monitoring with regard to metformin: take for 5 weeks then have a progesterone level measured evey 7-10 days to determine if ovulation has occurred. If progesterone is greater than 5 ng then it has. If ovulation is not detected after 5-10 weeks of metformin alone then add clomid (note the RE I worked for suggested 6 months of metformin before clomid)
So that explains, sorta, the reason for the increased metformin dose. I too think it is strange that people with type II diabetes only get 1000mg, when women with PCOS get doses much higher. My friend has told me on many occasions that the use of metformin in treating PCOS is cutting edge stuff, and that to some extent it hasn't filtered through to all levels of medical professionals. My GP didn't know about it until I told him, and while my gyn did know, he'd obviously not done enough reading. I'm also told that metformin has been found to be useful in treating PCOS even when there is no insulin resistance - probably for the same reason that some IVF docs put their patients on it regardless of PCOS or not, just for the simple fact that it seems to improve egg quality.