(CBS Local) — The U.S. Food and Drug Administration says it is investigating to see if a prescription drug used to treat diabetes is contaminated with traces of a chemical linked to cancer.

The impacted drug is metformin, which is used to control high blood sugar in patients with Type 2 diabetes.

Some metformin medicines in other countries have been found to contain the carcinogen N-Nitrosodimethylamine (NDMA), but those levels were in the “naturally occurring in food and water” range.

“While we are aware that some regulatory agencies outside the U.S. may be recalling some metformin drugs, there are no metformin recalls affecting the U.S. market at this time,” Dr. Janet Woodcock said in a statement last week.

“The FDA is investigating whether metformin in the U.S. market contains NDMA, and whether it is above the acceptable daily intake limit of 96 nanograms,” she continued.

The FDA recommends patients continue taking metformin to keep their diabetes under control because “there are no alternative medications that treat this condition in the same way.”

NDMA’s presence in blood pressure and heartburn medications — including Zantac — has prompted full recalls in the last year and a half.

The FDA says it is expanding testing requirements for such medications to ensure the drugs do not have NDMA above the acceptable daily intake limit.

If you have questions about the investigation, you can contact the FDA at 1-888-463-6332.