ST. LOUIS -- Several pharmacies in the St. Louis area are selling a new pseudoephedrine-based decongestant made by a suburban St. Louis company that claims the drug cannot be used to make methamphetamine.

Pseudoephedrine, which can be found in cold and allergy pills, is a vital precursor for most meth recipes. Missouri has been especially hard hit by the meth epidemic, leading the nation in meth lab seizures every year but one since 2003.

Emilie Dolan, spokeswoman for Highland Pharmaceuticals, said Tuesday that the suburban St. Louis company spent years coming up with a form of pseudoephedrine that couldn't be used in meth production, resulting in Zephrex-D. A key to making meth is crystallization, and Dolan said Zephrex-D interrupts the process because rather than crystallizing when heated with the chemicals, it results in a gooey substance.

The federal Drug Enforcement Administration had been reviewing the drug, but the status of its testing wasn't immediately clear Tuesday. The agency didn't return a phone message from The Associated Press.

Federal law requires stores to keep pseudoephedrine-based products behind the counter, and two states -- Mississippi and Oregon -- require a prescription.

In Missouri, there is no statewide prescription law, but more than 70 cities and counties have adopted prescription ordinances.

Dolan said some have agreed to exempt Zephrex-D from the prescription requirements, and the company is working with the others for exemptions. The drug began appearing on some pharmacy shelves in the last week or so, mostly in the St. Louis area, and Dolan said it could be distributed nationally within a year.

A website promoting Zephrex-D says it is available at Walmart stores in Cape Girardeau and Sikeston, Mo.

Jason Grellner, a narcotics officer in Missouri's Franklin County, has long been advocating for the technology. Earlier this year, he told a Missouri House committee "this is an option that ends clandestine meth labs" but still gives people access to pseudoephedrine.

Elizabeth Funderburk of the Consumer Healthcare Products Association, which represents large pharmaceutical companies, raised concerns about Highland seeking local exemption rather than approval from the DEA. She said her organization is "interested in any methods to prevent abuse and hope this proves to be an effective path forward."