The U.S. Food and Drug Administration announced new guidance on Sept. 1 for drugmakers, citing “serious concerns” that common medications including Zantac, Axid, metformin and angiotensin II receptor blockers might contain nitrosamines at potentially carcinogenic levels.

The guidance is intended to improve consumer safety by recommending steps to keep unacceptable levels of nitrosamines out of prescription and over-the-counter drugs, according to a statement from FDA Commissioner Dr. Stephen Hahn and Dr. Patrizia Cavazzoni, deputy director for operations of the FDA’s Center for Drug Evaluation and Research. 

Nitrosamines, according to the FDA, are chemicals commonly found in water and in foods such as cured and grilled meats, vegetables and dairy products. Nearly everyone is exposed to some level of nitrosamines, but exposure over long periods of time or to large amounts of the compounds may increase the risk of cancer. Nitrosamines have been linked to cancer in the lungs, brain, bladder, liver, kidney, stomach, throat and sinuses.

The new guidance sets an acceptable nitrosamine intake limit of 96 nanograms per day and encourages drug manufacturers to perform risk assessments, work closely with third-party drugmakers and regularly test medications for nitrosamine impurities. The 16-page document identifies five different types of nitrosamine drug impurities, including the most common N-nitrosodimethylamine (NDMA).

On April 1, the FDA requested immediate removal of Zantac and all ranitidine-containing generics from the market, citing concerns over the potential presence of NDMA in unacceptable levels. 

In November 2019 the FDA requested that manufacturers voluntarily recall Zantac, Axid and related generics if the agency or the manufacturer finds unacceptable levels of NDMA. Ranitidine syrups have been used to treat infants and children.

Hahn and Cavazzoni said that the FDA is working with regulators outside the U.S. to ensure the nation’s drug supply is free of unsafe levels of nitrosamine impurities.