A federal judge on Friday handed chain drug stores and community pharmacies a temporary victory by delaying a new federal rule that would have lowered the reimbursement rates for dispensing generic drugs in the Medicaid, the government health care program for the poor.

The National Association of Chain Drug Stores, which represents CVS, Rite-Aid, Walgreen’s and others, and the National Community Pharmacists Association, which reps the mom and pops, filed a lawsuit in a last-ditch effort to block a new formula that would have slashed their payments by billiongs of dollars. The new formula that the Centers for Medicare & Medicaid Services wants to adopt is Average Manufacturers Price, or AMP.

But US District Court Judge Royce Lamberth granted an injunction that will prevent CMS from adopting the formula, our friends at Drug Channels inform us. The pharmacies have been arguing that CMS that untold numbers will be forced to close their doors if reimbursements rates are slashed below their costs or drop out of Medicaid.

“We can’t emphasize enough how these Medicaid cuts would hurt low-income patients who may have difficulty acessing their prescription medications in the nation’s pharmacies,” NCPA ceo Bruce Roberts and NACDS ceo C. Anderson said in a statement.

This is the request for the injunction, and this is the order.

Hat tip to Drug Channels, which has a nice analysis.