How It Works
Metformin decreases the level of
androgens produced by the ovaries and adrenal glands.
It also helps the body use
insulin and may reduce the risk of
Why It Is Used
Metformin is a diabetes medicine
sometimes used for lowering insulin and blood sugar levels in women with
polycystic ovary syndrome (PCOS). This helps regulate
menstrual cycles, start ovulation, and lower the risk of miscarriage in women
with PCOS. Long-term use also lowers diabetes and heart disease risk related to
high insulin levels.1
How Well It Works
Metformin lowers insulin, androgen,
cholesterol levels. It also improves metabolism in
women who are insulin-resistant.
Metformin may help start ovulation in women with PCOS who have not responded to treatment with clomiphene. Some doctors may recommend taking metformin in addition to clomiphene to start ovulation.2
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
- Usually the benefits of the medicine are more important than any minor side effects.
- Side effects may go away after you take the medicine for a while.
- If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.
Call911or other emergency services right away if you have:
Call your doctor right away if you have:
Common side effects of this medicine include:
Reference for a full list of side effects. (Drug Reference is not available in
What To Think About
Blood levels of vitamin B12 can decrease in
women who take this medicine, but the lower level usually does not cause health
problems. Doctors do recommend that women who take metformin also take a daily multiple-vitamin supplement.
You may need to stop taking
metformin temporarily before major surgery or other medical procedures, such as
X-rays that use contrast dyes. Talk to your doctor
about this before your surgery or procedure.
The effect of
metformin may be increased if you also take cimetidine (Tagamet). Before you take
metformin, talk with your doctor about any other medicines you are
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
Advice for women
If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
Ehrmann DA (2005). Polycystic ovary syndrome.
New England Journal of Medicine, 352(12):
Fritz MA, Speroff L (2011). Chronic anovulation and the
polycystic ovary syndrome. Clinical Gynecologic Endocrinology and Infertility, 8th ed., pp. 495–531. Lippincott Williams and
Primary Medical Reviewer
||Patrice Burgess, MD - Family Medicine
Specialist Medical Reviewer
||Kirtly Jones, MD - Obstetrics and Gynecology
Current as of
||March 12, 2014