A bill to block a controversial Medicare payment experiment would increase government spending by $395 million over the next decade, a nonpartisan agency found.

The bill would prevent the Obama administration from implementing a proposal to modify payments made to doctors for prescription drugs covered in Medicare Part B. Doctors currently get paid by the federal government the average sales price of the drug and a 6 percent add-on, while the proposal would change that to 2.5 percent plus a flat fee of $16.80 per drug per day.