The U.S. Food and Drug Administration said on Thursday it approved Pfizer’s Chantix tablet to help cigarette smokers stop smoking. The active ingredient in Chantix (varenicline tartrate) works on brain sites affected by nicotine, the FDA said.

The drug provides some nicotine effects to ease the withdrawal symptoms and also blocks the effects of nicotine from cigarettes if they resume smoking, the agency said.

Chantix received a priority FDA review because of its “significant potential benefit” to public health, the agency said.

“Tobacco use, particularly cigarette smoking, is the single most preventable cause of death in the United States and is responsible for a growing list of cancers as well as chronic diseases including those of the lung and heart,” Dr. Scott Gottlieb, FDA deputy commissioner, said in a statement.

“The agency is committed to helping facilitate the development of products to help people quit smoking and improve their overall quality of life,” he added.

An estimated 44.5 million U.S. adults smoke cigarettes, and more than 8.6 million of them have at least one serious illness caused by smoking, according to the federal government.