Updated

Cold remedies that can be used by drug dealers to make methamphetamine would be forced behind store counters under legislation Congress is poised to pass by year's end.

Lawmakers hope that federal restrictions — included in the agreement reached Thursday to reauthorize the USA Patriot Act — will stem a meth trade that has hit rural America particularly hard.

A number of states have already moved to curb the sale of cold pills containing pseudoephedrine, the ingredient used to cook meth in makeshift labs. The federal law would prevent meth makers from moving to states with weaker laws.

Stores would be required to keep medicines like Sudafed and Nyquil behind the counter and consumers would be limited to 3.6 grams, or about 120 pills, per day and 9 grams, or about 300 pills, a month. Purchasers would also need to show a photo ID and sign a logbook.

Those limits target meth dealers who buy large quantities of the drugs to extract the pseudoephedrine.

The measure is a compromise reached after months of haggling over the 30-day limit. Sens. Jim Talent, R-Mo., and Dianne Feinstein, D-Calif., who pushed the legislation in the Senate, insisted the limit was needed to curb the meth epidemic.

"The heart of this legislation is a strong standard for keeping pseudoephedrine products out of the hands of meth cooks," Feinstein said.

Under the bill, stores with pharmacies would have to keep the medicine behind the pharmacy counter. Stores without pharmacies could sell cold medicines from a locked case behind a store counter if they gain approval from the Drug Enforcement Administration.

"We're pleased to see the current compromise," said Tim Hammonds, president and CEO of the Food Marketing Institute, which represents grocery stores and other retailers. "It addresses a serious law enforcement concern, but in a way that balances the need for consumer access to safe and effective products."

Hammonds said he was disappointed the federal bill would not pre-empt more restrictive laws in states like Oklahoma and Iowa, where cold remedies are sold from behind pharmacy counters. At least 37 states have enacted laws to restrict the sale of cold medications to starve meth manufacturers of their key ingredient.

Many leading retailers — including Kmart, Walgreens, Target, Wal-Mart — have already adopted guidelines to limit customer access to cold products or to limit their sales.

Some drug makers have changed the ingredients in cold pills to take out pseudoephedrine and replace it with another substance, phenylephrine, that cannot be used to make meth. A new product called Sudafed PE, is already on store shelves, though the old Sudafed is still available.

The measure would provide nearly $100 million a year for five years to train state and local law enforcement to nab meth offenders and would expand funding to prosecute dealers and clean up environmentally toxic meth labs.

Talent called the measure "the toughest anti-meth bill ever considered by Congress." He predicted that it would help reduce the number of clandestine labs where the illegal drug is made with common items like household cleaners and coffee filters.

The meth problem is particularly severe in the Midwest, where rural areas provide cover for the pungent chemical odor from meth labs. In Missouri, law enforcement officers seized more than 2,700 meth labs last year — more than any other state.

Passage of the measure could take place as early as next week, when Republican leaders press for a vote on the anti-terrorism bill. Some opponents who claim Patriot Act threatens civil liberties are threatening a filibuster unless changes are made.