Klobuchar, a Minnesota Democrat, along with Robert Casey, a Democrat from Pennsylvania, introduced a bill that would force drug companies to tell the Food and Drug Administration about looming shortages. The FDA said early notification helped it to prevent 99 shortages in 2011.

But the legislation has been stuck in a deadlocked Congress since February 2011, despite support from Republican and Democratic lawmakers, as well as the White House.

Klobuchar said she would try to include it as an amendment to the transportation bill.

"We acknowledge drug shortages may not have a lot to do with highways," Klobuchar said. "Maybe we have to try every bill, but we can't wait a year to get this done."

Klobuchar's sense of urgency comes after reports that the supply of methotrexate, a drug used to treat children with acute lymphoblastic leukemia, may run out in a matter of weeks.

"Without this drug, patients are at a dramatically heightened risk of dying," Klobuchar said in a statement, adding that the drug had cure rates close to 90 percent.

The number of drugs in short supply rose to 220 in 2011 from 56 in 2006 -- the year a clear trend started emerging.

Doctors and patient advocates say shortages of certain drugs, such as some chemotherapy treatments and antibiotics, have forced providers to postpone care or use second-best or costlier alternatives.

President Barack Obama made shortages a national priority with an executive order in October, and urged Congress to quickly pass legislation to address the issue.

But Klobuchar's drug shortages legislation is only a short-term solution, as lawmakers and regulators remain divided about the root causes of the problem.

"We have always acknowledged the amendment is more getting at the short-term problem," Klobuchar said. "But you have to get at the short-term problem, because otherwise people are doing to die."

• A Permanent Economic Emergency