WEDNESDAY, Feb. 4 (HealthDay News) -- In a continuing effort to prevent counterfeit and adulterated medications from reaching American consumers, the U.S. Food and Drug Administration is adopting stricter standards for heparin and glycerin -- two widely used drug products at the center of recent contamination episodes.

The new standards were created by the U.S. Pharmacopeia (USP) Convention, a nonprofit health organization that sets public standards for prescription and over-the-counter medicines and other health-care products made or sold in the United States.

"These are ongoing changes for our standards for heparin, and for glycerin that might be contaminated with toxins called ethylene glycol and diethylene glycol," said USP Chief Science Officer Dr. Darrell R. Abernethy. "The reason is to protect the public health."

Starting in November 2007, there were hundreds of severe reactions among patients receiving heparin, a blood thinner, and most were patients on kidney dialysis. Some 200 people died from the reactions, Abernethy said.

"There was almost certainly a contaminate put in the heparin in China that caused these reactions," he said. "It was done in such a clever, devious way that it passed our standards."

The contaminated heparin from China was tainted with over-sulfated chondroitin sulfate, which is made from the dietary supplement chondroitin and mimics heparin's blood-thinning properties, Abernethy explained.

The USP had to fix the standard so that adulterated heparin would not be allowed to come into the United States, Abernethy said. In a first step, the USP did a "quick fix" last year, which dealt with the immediate problem from China.

Now, there will be a permanent change in the standard that takes effect in August. After that time, manufacturers and importers of heparin will have to use the new standard to test their products before they can be sold in the United States. The new standard includes a specific chemical identification of heparin that spots the chemicals in the heparin more precisely than was done before, Abernethy said.

Glycerin is a chemical used to sweeten products such as toothpaste and pancake syrup, while ethylene glycol and diethylene glycol are poisonous. Switching ethylene glycol, which is used in antifreeze, as a cheap substitute for glycerin goes back as far as 1937 when more than 107 people were killed in the United States by ethylene glycol used as a liquid base for an antibiotic, Abernethy said.