Story highlightsThe FDA recently recalled certain drugs containing valsartanHere's what patients should know, including alternatives and cancer risk (CNN)Several common drugs that contain valsartan, used to treat high blood pressure and heart failure, were recalled in the United States on Friday due to an "impurity" in the drug that poses a potential cancer risk.That impurity, N-nitrosodimethylamine or NDMA, is classified as a probable human carcinogen, based on results from lab tests.The medicines included in the voluntary recall are valsartan from Major Pharmaceuticals, Solco Healthcare and Teva Pharmaceuticals Industries, as well as valsartan/hydrochlorothiazide from Solco and Teva.Valsartan is off patent and is used as a component of other generic medicines, but not all medicines containing the ingredient are involved in the recall.The US Food and Drug Administration noted in a news release that "the presence of NDMA was unexpected" and thought to be related to changes in the way the active substance was manufactured.Read More"Our drug shortages team is also working hard to ensure patients' therapeutic needs are met in the United States with an adequate supply of unaffected medications," FDA Commissioner Dr. Scott Gottlieb said in the statement.FDA joins 22 countries' recall of common heart drugThe FDA action came after 22 other countries issued recalls involving 2,300 valsartan batches sent to Germany, Norway, Finland, Sweden, Hungary, the Netherlands, Austria, Ireland, Bulgaria, Italy, Spain, Portugal, Belgium, France, Poland, Croatia, Lithuania, Greece, Canada, Bosnia and Herzegovina, Bahrain and Malta.Now, the US recall has left some patients who take valsartan-containing drugs scratching their heads over what to do about their treatment regimens."Their biggest concern is about their risk of cancer and better understanding how concerned they should be," said Dr. Suzanne Steinbaum, director of women's cardiovascular prevention, health and wellness at Mount Sinai in New York and a spokeswoman for the American Heart Association."They are asking if there is any testing that should be done. Patients are now asking if they should only request 'brand-name' medication instead of generic in order to make sure that this doesn't happen. Lastly, they all want to stop the medication," Steinbaum said, noting that's not the correct action to take. Experts offered four main takeaways for patients in the wake of the recall.Not all valsartan drugs have the 'impurity'In general, not all medications containing valsartan are included in the recall, because not all valsartan-containing medicines were provided the valsartan supply linked to the NDMA "impurity."Since the recall, the external supplier linked to the problem has stopped distributing its valsartan ingredient, and the FDA has been working with the affected companies to reduce the chances of such a recall occurring in future products, according to the agency. JUST WATCHEDWhy is high blood pressure a '