When consumers get a prescription drug from the pharmacy, they assume that it’s been tested and is safe to use. But what if a drug changes in harmful ways as it sits on the shelf or in the body? One dangerous result has been the creation of N-nitrosodimethylamine (NDMA), a probable carcinogen, in certain drugs. NDMA is found in chlorinated water, food, and drugs in trace amounts. To minimize exposure, the Food and Drug Administration has set an acceptable level of NDMA in each pill at less than 96 nanograms. But over the past few years, the FDA has found excessive amounts of NDMA in several drugs for hypertension, diabetes, and heartburn. As a result, the agency has initiated recalls to protect the public. These products were contaminated with NDMA during the manufacturing process. The FDA recommended best practices for manufacturers to minimize this risk going forward. Unfortunately for the buying public, emerging …