The Many Benefits of Metformin

BY CARL A . GIBSON, MD

Metformin (also known by the brand names Glucophage®, Glucophae XR®, Glumetza®, Fortamet® and Riomet®) is one of the most popular drugs available for the treatment of type 2 diabetes mellitus, a form of diabetes in which the body is unable to use insulin efficiently, often leading to less insulin production over time. Introduced in the United Kingdom in 1958, Canada in 1972 and the United States in 1995, metformin is now believed to be the most widely prescribed antidiabetic drug in the world.

Originating in a common plant native to the eastern part of the U.S. called French lilac or goat’s plant, metformin has been used to treat many conditions, including tuberculosis, rheumatism and bladder problems. Seminole Indians are said to have used the root, which contains the natural insecticide rotenone, to stun fish for easy harvesting. Other reported uses have included pouring a brew made from the roots on garden plants to kill insects. And at one time, this plant was fed to goats as it was thought to improve milk production, thus the name goat’s rue.

What researchers have learned in the past several years is that metformin has many other positive benefits beyond controlling blood glucose levels with very low risk of causing hypoglycemia (low blood sugar). One major effect of metformin is a decrease in the production and release of glucose from the liver. When used in combination with antidiabetic drug sulfonylurea or insulin, metformin also can help minimize the weight gain frequently associated with these medications. It can lower LDL (bad) cholesterol, lower blood fat levels and reduce the risk of cardiovascular disease. And when taken by individuals treated intensively with sulphonylureas, a class of oral medications that control blood sugar levels in patients with type 2 diabetes by stimulatingproduction of insulin, or insulin alone, metformin also significantly decreased the risk of stroke.

Although metformin is primarily used in the treatment of type 2 diabetes, it has also been safely used to treat diabetes that develops during pregnancy (gestational diabetes). In overweight individuals with prediabetes, it can help delay or prevent the development of full-blown diabetes.

Another positive is that metformin has few side effects, the most common being nausea and diarrhea. These effects can sometimes be avoided or minimized by taking a lower dose or extended release form of metformin.

Metformin may also play a role in preventing cancer (having type 2 diabetes is a major risk factor for developing certain cancers). Studies in humans suggest that if you have diabetes and are taking metformin, you have a lower risk of developing cancer than if you do not take metformin. Although whether this is related to being overweight, which is common in those with type 2 diabetes, the natural production of more insulin, which is considered a stimulus to cell growth, or some other factor is unknown. Still, in studies using tissue cells, metformin can inhibit the growth of breast, colon, lung, pancreatic and prostate cancer cells.

What’s more, a recent study suggested those with diabetes who take metformin reduce their risk of open angle glaucoma (pressure in the eyes) by 21 percent. Another report looking at the results of sleep studies suggested that people with diabetes who take metformin had better sleep, or if they had evidence of sleep apnea, it appeared to be less severe. And there is even evidence that metformin might be good for bone density, with a positive effect on specific cells involved in bone formation. Recent studies have examined whether the use of metformin in those with kidney disease may be much safer than originally thought. Similarly, in people who have a chronic condition such as congestive heart failure, there is accumulating evidence that metformin again might be much safer than researchers initially theorized.

So what message should you take from all of this information? The benefits of metformin are numerous and, many could argue, outweigh any potential risks. If you take metformin or have recently been prescribed the medication and have concerns about its possible negative effects, take the time to discuss your concerns with your endocrinologist and diabetes care team at your next appointment.

Dr. Carl A. Gibson is a board-certified endocrinologist and Physician Practice Director for Riverside Endocrinology and Diabetes Specialists located in Newport News, Virginia. He practiced medicine for over 22 years while on active duty as a commissioned officer in the U.S. Army. He was last stationed at Madigan Army Medical Center in Tacoma, Washington, where he served as Chief of Endocrinology and Medical Director of the Diabetes Care Center before retiring from active duty in 2009. He volunteers for several local community and national non-profit organizations.