Popular Diabetes Rx May Have New Destination in the Body

Metformin delayed-release targets gut, limits bloodstream absorption in diabetes patients

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) A new form of a popular medication might change the game for some patients with type 2 diabetes.

A new study from the University of North Carolina found that the mechanism of action of popular diabetes medication metformin (brand names Glumetza, Fortamet, Glucophage, Riomet) may primarily happen within the intestines — not within the bloodstream, as was previously thought.

"The authors propose that metformin works in the lower intestine (rather than in the bloodstream) to exert its blood sugar lowering effects," said E. Lee Carter, RPh, a clinical pharmacy specialist at the Huntington VA Medical Center in Prestonsburg, KY, in an interview with dailyRx News. "This finding could be pivotal for many diabetic patients who cannot otherwise tolerate metformin due to its propensity to cause kidney damage."

Dr. Carter was not involved with this study.

Metformin is the most commonly prescribed initial medication to treat type 2 diabetes.

Many diabetes patients also have kidney damage, however, which can hinder the clearance of metformin from the blood.

Accumulated metformin can lead to a dangerous metabolic state and additional kidney damage. Therefore, metformin is not advised for diabetes patients with kidney damage.

According to Dr. Carter, metformin's use is limited to as many as 40 percent of diabetes patients as a first-line treatment.

This study, led by John Buse, MD, PhD, the director of the Diabetes Care Center at the University of North Carolina, focused on a type of delayed-release metformin called metformin-DR.

Delayed release delivers the medication to the lower intestine where minimal absorption in the blood may take place.

This study included two trials.

In trial 1, healthy patients were given metformin that released at different times. Those given metformin-DR were found to have 50 percent less in their blood.

In trial 2, 240 patients with type 2 diabetes were given either metformin-DR, metformin-XR (extended release) or a placebo.

Metformin-DR showed a 40 percent increase in apparent potency over metformin-XR.

Dr. Buse and team concluded that metformin-DR was effective at lowering blood sugar and may be less risky for diabetes patients with kidney damage.

This study was published Aug. 18 in the journal Diabetes Care.

Elcelyx Therapeutics funded this research.

Study authors disclosed multiple ties to pharmaceutical companies, including Elcelyx Therapeutics.

Review Date: 
August 20, 2015
Last Updated:
August 30, 2015