The US Food and Drug Administration (FDA) has issued a health warning regarding products containing tianeptine, which is often called “gas station heroin” because of its easy availability at gas station stores.

The FDA noted that tianeptine is associated with an increasing number of adverse events, including death.

Other associated adverse events cited by the agency include coma, agitation, confusion, hypertension, respiratory depression, tachycardia, and vomiting.

The product is licensed as an atypical antidepressant in some countries and is commonly prescribed for oral intake at 12.5 mg thrice daily. However, because higher doses can produce euphoria, its use has been restricted and a warning has been added to its drug label about possible addiction.

Tianeptine has not been approved by the FDA for any medical use in the United States, is not scheduled under its Controlled Substances Act, is not considered to be safe in food, and has not met regulations as a dietary ingredient “Nevertheless, tianeptine is being marketed as a ‘research chemical,’ a ‘nootropic’ cognitive enhancer, or a dietary supplement,” the agency reported.

In addition to gas stations, the product — which also goes by names such as Tianaa, Zaza, Neptune’s Fix, Pegasus, and TD Red — is often available at vape and smoke shops, and online retailers.

The FDA noted that unlike the 37.5 mg total daily dose amount recommended by countries that have approved the product for depression, there have been reports of individuals in the United States ingesting doses from 50 mg to 10,000 mg.

So far, the agency has sent warning letters to companies that distribute and sell products that contain tianeptine. In addition, it has issued an import alert to help detain shipment of the products containing the drug at US borders.

Tianeptine may not be identified in routine drug-screening panels.