Drug Helps Prevent Type 2 Diabetes June 13, 2002 -- A drug with an excellent safety record can delay or even prevent type 2 diabetes. The downside: the drug tends to give people gas.

People on their way to developing type 2 diabetes go through a phase called impaired glucose tolerance (IGT). It's a bad sign. It means that the body's blood-sugar control system is already out of whack.

Now a study reported in the June 15 issue of The Lancet finds that the diabetes drug Precose can delay or even prevent diabetes in people with IGT. There's even more good news. Over time, the drug can let the blood-sugar system go back to normal.

As drugs go, Precose has a terrific safety record. But there's a downside: many patients find that it gives them gas and/or diarrhea. Study co-author Robert G. Josse, MD, is chief of medicine at St. Michael's Hospital, Toronto, Ontario, Canada.

"It does cause a bit of excess gas, wind, tummy upset, and diarrhea," Josse tells WebMD. "If it is taken properly, the amount of gas and wind is either a small nuisance or no problem. For those that tolerate it, this drug is a great benefit. It will be used to prevent diabetes and it will be effective and it will be safe."

The study found that those who took Precose for 3.3 years had a 25% lower risk of going from IGT to diabetes than those who took an identical-looking placebo.

That's pretty good -- but there's an even better way to prevent diabetes. Josse notes that simply by eating less and getting moderate exercise, a person with IGT can cut the risk of diabetes by 58%. Although it hasn't been proved in a clinical trial, Josse says that combining this kind of lifestyle change with Precose might further reduce diabetes risk.

Precose is more frequently used in Europe and Canada than in the U.S., says Patrick H. Bowen, MD, endocrinology section head at Atlanta's Emory University Clinic. One reason is that another diabetes drug, Glucophage, is more often prescribed. Another reason is patient preference.

"Precose has some advantages over Glucophage because it acts only on the bowel," Bowen tells WebMD. "But Precose is not used that much in this country. It is not very well tolerated in [the gastrointestinal] tract. The doses used in this study are the high doses linked to more intolerance. I have only two patients with diabetes who tolerate Precose."

Bowen and Josse note that no drug currently is approved for diabetes prevention. But both say that many doctors give off-label prescriptions for Glucophage to some IGT patients.