A coalition of drug manufacturers is working on a plan to help millions of low-income seniors pay for drugs when they hit the so-called doughnut hole in the new Medicare drug benefit. But the government warned such a plan to bridge the program's coverage gap could run afoul of antikickback laws unless properly structured.

The drug manufacturers have dubbed their plan Bridge Rx. When Medicare patients' drug bills reach $2,250 in a year, or amount to $750 out of their own pockets, they hit this doughnut hole at which the Medicare plans stop paying the drug costs (or in some cases pay much less). The plans resume payment after the patient's drug bills top $5,100, or total $3,600 in out-of-pocket costs.