(NewsNation) — An unregulated drug used to treat depression in some foreign countries and known to cause painful side effects is available for sale in some U.S. gas stations and convenience stores, concerning lawmakers.

Tianeptine is not approved in the United States by the Food and Drug Administration. It’s been linked to serious harm, overdoses and deaths, according to the FDA.

Tianeptine’s side effects include irritable bowel syndrome, stomachaches, drowsiness, mental confusion, shallow breathing and a slow heart rate. The FDA has said it has the potential to be abused and can even be addictive.

Because there’s no federal ban on the substance, it’s offered for sale in some gas stations and convenience stores, which concerns some lawmakers.

Rep. Wiley Nickel, D-N.C., said Wednesday on “NewsNation Now” that people don’t understand how dangerous it really is.

“This stuff is very addictive,” Nickel said.

On Tuesday, the FDA announced that Neptune Resources, LLC recalled all lots of Neptune’s Fix Elixir, Neptune’s Fix Extra Strength Elixir and Neptune’s Fix Tablets, which all contain tianeptine. About 12 states have banned tianeptine.

Nickel is part of a group of bipartisan lawmakers calling on the FDA to take action to keep people safe.

“It’s just about educating people about these issues,” Nickel said, adding he thinks more bans will come as people learn about tianeptine. Still, he added, “we have a responsibility to lead at the federal level, too.”

“We need to make sure that folks are aware of the dangers, and that’s the first thing we can do,” Nickel said.