When Adam Clark-Joseph’s infant daughter was prescribed ranitidine syrup for acid reflux, the same medicine used in the brand-name medicine Zantac, he was hesitant. Was there anything in the syrup that could harm his little girl? It was easy to find out. Clark-Joseph is the cofounder of independent pharmacy Valisure, which distinguishes itself by testing every batch of drugs it sells to ensure purity.
This careful attention to product quality led the pharmacy in 2018 to discover the probable human carcinogen NDMA in valsartan, a drug used to treat high blood pressure and heart failure. While no studies have been performed, to date, to identify the specific cancer risks NDMA poses, the impurity has been found to cause cancerous tumors in laboratory animals. Upon its discovery of NDMA in valsartan, Valisure notified the Food and Drug Administration (FDA), which led to further testing and a wave of valsartan recalls, as well as recalls of similar drugs in the class known as ARBs. The NDMA contamination was believed to have occurred during the manufacturing process.
Valisure ran tests on ranitidine and, sure enough, the results were rattling. “Every batch of every bottle of every manufacturer showed the same results—tremendously high formation of NDMA,” Valisure CEO David Light told Wired.
Unlike contamination occurring during manufacturing, the issue with ranitidine appeared to be an instability with the drug, Light explained. For example, when exposed to heat, such as in a hot car, the level of NDMA could increase well above the acceptable daily limit. Valisure also posed whether levels of NDMA could increase in the body after ingestion. For example, if it came in contact with sodium nitrate, which is found in processed meats and preservatives.
Once again, Valisure brought its findings to the FDA. The agency notified the public and conducted their own tests. One by one, prescription and over-the-counter versions of Zantac were recalled when their drugs tested positive for NDMA. Valisure submitted a Citizen’s Petition to the FDA calling for a suspension of sales of all Zantac products.
On April 1, the FDA issued a safety communication calling for the removal of all versions of Zantac from the market. The reason? Exposure to heat – such as when it is transported during distribution – as well as a longer shelf life raised NDMA in Zantac to disturbing levels.
Several lawsuits have been filed against Sanofi and other manufacturers of Zantac products alleging the companies knew for months that their heartburn medicine contained a probable cancer-causing impurity but failed to adequately warn consumers.