Several pharmacists told the Chicago Tribune they received an e-mail last week from Boyd Haley, president of the company that makes the product, informing them that OSR#1 would not be available after Thursday.
The product, sold as a toxicity-free antioxidant supplement, was featured on autism Web sites such as Age of Autism, whose managing editor described sprinkling it in her children's juice and breakfast sandwiches.
The Tribune reported in January that the compound had been developed as an industrial chemical used to treat mining wastewater, an issue apparently first raised by blogger Kathleen Seidel of neurodiversity.com.
On June 17, the FDA sent Haley a warning letter calling the product an unapproved new drug with false or misleading labeling regarding side effects. Failing to correct such violations can result in fines, seizure of products and even criminal prosecution.
Haley did not respond to requests for an interview Monday. An FDA spokeswoman said the agency had not heard from Haley or CTI Science.
Ellen Silbergeld, an expert in environmental health who is studying mercury and autism at Johns Hopkins University's Bloomberg School of Public Health, urged the FDA to monitor the company to ensure it does not continue selling the product.
"It is welcome news, but in these conditions, without government action, the situation remains unsettled," Silbergeld said.
A number of pharmacies listed on the CTI Science Web site as sellers of the product reported they were no longer selling OSR#1.
"We sold out last week," said pharmacist Kurt Moyer of Dr. Aziz Pharmacy in Indianapolis, which last week posted a message on the company Facebook page: "OSR#1 will no longer be available after July 29, 2010 and there is no anticipated release date, so once we sell out we will not be able to order additional stock."
Forrest Health urged customers to stock up while they still could. On Monday, online customers wanting to purchase OSR#1 were required to buy a minimum of three 30-capsule boxes at $60 each.
"OSR is going off the market," the site declared Friday. "We are stocking up as much as we can but supplies are going fast. We suggest you purchase large quantities if you want to assure availability."
Calls to Forrest Health were not returned.
The FDA's warning letter was enough to prompt John Koutsaris, president of Spectrum Supplements in Olean, N.Y., to stop selling OSR#1. "Obviously, the No. 1 concern for us is the health of the customer," Koutsaris said.
According to Koutsaris, Haley indicated in his e-mail that he would be seeking approval for OSR#1 as a new drug from the FDA. That process can cost hundreds of millions of dollars and take many years with no guarantee of success.