More than 580,000 bottles of the blood pressure drug prazosin hydrochloride have been recalled nationwide after tests found potential contamination with a cancer-causing chemical. The FDA announced that Teva Pharmaceuticals and distributor Amerisource Health Services issued the voluntary recall after discovering nitrosamine impurities — compounds linked to higher cancer risk with long-term exposure.

Prazosin is commonly used to treat high blood pressure by relaxing blood vessels and is sometimes prescribed off-label for PTSD-related nightmares. The recall was classified as Class II, meaning short-term use is unlikely to cause serious harm, but extended exposure may increase cancer risk.

Nitrosamine contamination can occur during manufacturing or storage, especially when drugs are exposed to heat or light. The FDA is urging drugmakers to strengthen quality controls and is advising patients not to stop taking their medication without consulting a doctor. Anyone concerned can check the FDA’s recall database or contact their pharmacy to see if their prescription is affected.