Pfizer (PFE) has issued a recall for 12 lots of its smoking-cessation medication Chantix because it may have a cancer risk due to possible higher-than-acceptable levels of N-nitroso-varenicline – a cancer-causing impurity.

According to the recall notice, long-term ingestion of N-nitroso-varenicline can pose a cancer risk to humans, but there is not an immediate danger to patients who are currently taking the recalled Chantix medication.

N-nitroso-varenicline is a nitrosamine impurity, which is commonly found in water and foods such as cured and grilled meats, dairy products, and vegetables. Some exposure to nitrosamine is normal, but high levels can result in increased cancer risks, the Food and Drug Administration said.

However, the FDA also said that the risk of smoking, which Chantix is used to help people control, is higher than the cancer risk from the nitrosamine impurity in N-nitroso-varenicline.

The recalled Chantix medication affects two lots of 0.5 mg tablets, two lots of 1 mg tablets, and eight lots of 0.5/1 mg tablets. The drug was distributed nationwide from June 2019 to June 2021. A complete list of medication affected by the recall can be viewed here.

Anyone who has the recalled medication in their possession should see their healthcare provider for an alternative treatment before stopping the drug.

Affected patients should call Stericycle Inc. at 1-888-276-6166, Monday through Friday, from 8 a.m. to 5 p.m. ET for instructions on how to return the recalled medication and obtain a reimbursement for the cost of the drug.

Shares of Pfizer were trading at $41.54 as of 10:21 a.m. EDT on Tuesday, up $1.39, or 3.47%.

Smoking Cigarettes Stop Philip Morris U.K. Managing Director Peter Nixon appeared on 'Good Morning Britain' on Wednesday, where he told viewers that they should give up cigarettes for heated tobacco products. A cigarette smoker is pictured on March 1, 2018, in Lille, northern France, on the day when the price of a packet of cigarettes was increased by one euro to fight against smoking. The government plans regular increases to bring the cost of a packet to 10 euros by 2020. Photo: Getty Images/PHILIPPE HUGUEN