The real-time, stop-sale system used by the state of Iowa in pharmaceutical sales has stopped the sale of 14,000 boxes of medicine that contain pseudoephedrine, an ingredient in the methamphetamine.

Stop-sale is used in 24 states across the country, according to the National Association of Drug Diversion Investigators.

The system keeps track of how many purchases ofpseudoephedrine an individual has made and declines sales to them if they have exceeded the legal limit, according to the Consumer Healthcare Products Association.