Five members of Congress have asked the head of the U.S. Food and Drug Administration what the agency is doing to address use of tianeptine, otherwise known as “gas station heroin.”

In a Jan. 18 letter to FDA Commissioner Dr. Robert Califf, Reps. Jeff Jackson (D-N.C.), Rich McCormick, M.D. (R-Ga.), John Rose (R-Tenn.), Lauren Boebert (R-Colo.) and Wiley Nickel (D-N.C.) urged “FDA to take immediate action to research and provide guidance on tianeptine use.”

Tianeptine is an “extremely addictive” substance that features opioid-like properties, is widely sold as a supplement, and has not been approved for any medical use by FDA, according to a press release from Jackson’s office. Lawmakers wrote to Califf after the New York Times published an article on tianeptine.

Nine states — Alabama, Michigan, Mississippi, Tennessee, Georgia, Indiana, Ohio, Florida and Kentucky — have already moved to ban or control tianeptine sales, Jackson’s office said.

U.S. lawmakers, however, want to know what FDA is doing to oversee tianeptine, beyond warnings it issued in 2018, 2022 and 2023.

“The urgent need for FDA action on tianeptine cannot be overstated,” the members of Congress concluded in the letter to Califf. “It is vital to support legislative or administrative initiatives that strengthen FDA oversight and provide states greater ability to protect our communities from the dangers posed by substances like tianeptine.”

Related:Tianeptine products voluntarily recalled following FDA letter to retailers

Lawmakers requested Califf identify FDA research to determine the pharmacological properties of tianeptine, and the effects on human health of regular or over-usage of tianeptine. They also asked FDA “in what ways, if any” the agency is “working with federal and state law enforcement, public health agencies, and advocacy groups to better understand the marketing and distribution of tianeptine and its effect on public health.”

Finally, the congressional letter inquired whether FDA has taken steps in conjunction with the Drug Enforcement Administration (DEA) to study whether tianeptine should be scheduled under the Controlled Substances Act.

“Recent reporting indicates that tianeptine is extremely addictive and that tianeptine withdrawal symptoms are strikingly similar to opioid withdrawal symptoms, including nausea, chills and insomnia,” wrote lawmakers, who added medical research suggests “tianeptine can cause fatal overdoses.”

An FDA spokesperson said the agency has received the letter and will respond directly to the members of Congress.

Dan Fabricant, Ph.D., who oversaw FDA’s Division of Dietary Supplement Programs during the Obama administration and presently leads the Natural Products Association (NPA), said the tianeptine issue “stems from a lack of enforcement.”

FDA doesn’t need additional authorities or new resources to tackle the problem, according to Fabricant, who said “this is an issue of willpower.”

“FDA has been aware of tianeptine for some time (2020) and it’s unclear that there has been a consistent initiative to address it,” he added. Fabricant questioned why the agency cannot get firms to voluntarily recall their products or take other basic actions, including writing letters to gas stations selling tianeptine.

According to FDA, tianeptine does not qualify as a dietary ingredient, is an unsafe food additive, and supplements containing it are adulterated under the Federal Food, Drug & Cosmetic Act. FDA says tianeptine also is known as tianeptine sulfate, tianeptine sodium powder, tianaa, tianna green, tianna red and tianna white.

Not only are some companies illegally selling and marketing tianeptine, “They are also making dangerous and unproven claims that tianeptine can improve brain function and treat anxiety, depression, pain, opioid use disorder, and other conditions,” FDA warned in a 2022 consumer update.

FDA reported people have suffered harmful effects from abusing or misusing tianeptine by itself or with other drugs, including antidepressants and anti-anxiety medicines. Among the harmful effects FDA listed: agitation, coma, confusion, death, drowsiness, high blood pressure, nausea, rapid heartbeat, slowed or stopped breathing, sweating and vomiting.

Per the 2022 consumer update, FDA has issued warning letters to companies unlawfully marketing tianeptine products as dietary supplements and unapproved drugs and also issued import alerts to stop tianeptine from entering the U.S.

FDA in November 2023 warned consumers not to buy or use any of Neptune’s Fix products or any product with tianeptine.

“FDA has received severe adverse event reports after use of Neptune‘s Fix products, including seizures and loss of consciousness leading to hospitalization,” the FDA warning said. “Consumers who experience a bad reaction to any tianeptine product should seek immediate medical help.”