Metformin (Glucophage XRGlumetzaFortamet, Riomet)


Please note these instructions are intended for Princeton IVF patients. If you are not under our care, you should consult your physician about the use of this or any other medications or treatments.

Metformin is a diabetes drug that is used in women diagnosed with polycystic ovarian syndrome (PCOS). 

It is believed to work by improving insulin sensitivity, which is commonly associated with PCOS.  By lowering your insulin level, metformin allows many women to cycle more normally.  If you require other medications such as clomid or injectables, it may help to improve your response to these medications.  Once started on metformin, you should continue the medication even if we go onto other treatments.

The side effects of metformin include diarrhea, cramping and bloating. These symptoms will usually improve with time. You may also experience a 10-15 lb weight loss.  The only serious side effect is called lactic acidosis.  This happens in patients with diabetes; whether it can happen with PCOS alone is unclear.  For this reason, we ask you to drink plenty of water and if you develop a stomach virus to stop the medication for a day or two.

You will start the metformin at a dose of 500mg daily with meals, for the first week.  The second week, you will take the pills twice a day with meals. From the third week on, you will take them three times a day.  The Glucophage XR and Metformin ES (or virtually any metformin that contains initials after the name) pills can be taken all at once with dinner.  Do not increase the dose each week if you are having severe problems with side effects.

It is also felt that women with PCOS will benefit from a low carbohydrate diet.  Extreme low carb diets such as Atkins are effective but difficult to maintain.  Other low carb diets such as Sugar Busters, the Insulin Resistance Diet or South Beach may be more useful. 

Several studies have demonstrated a significant reduction in miscarriage rates by continuing the metformin.  At this time, metformin use in pregnancy appears to be safe.  For this reason, we encourage you to continue the medication until 12 weeks pregnancy. Beyond, that it may reduce your chance of gestational diabetes, your should not continue past 12 weeks unless advised to do by your Obstetrician, Perinatologist or Endocrinologist.

For more information on PCOS, you can go to:

For more information on carbohydrate content in foods, you can go to