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A dangerous substance dubbed "gas station heroin" continues to alarm medical professionals, with more states making moves to restrict or ban tianeptine.

Fourteen states have officially classified the tricyclic antidepressant as a Schedule I controlled substance.

Connecticut is the latest state to crack down, officially banning the sale and use of the substance starting on Wednesday.

HEALTH OFFICIALS WARN OF DANGEROUS SUBSTANCE AVAILABLE IN STORES ACROSS THE NATION

Tianeptine, which can produce euphoria in higher doses, can be more potent than morphine and addictive opioids, according to the U.S. Food and Drug Administration.

Some countries have taken steps to restrict how tianeptine is prescribed or dispensed, and have even revised the labels to warn people of its potential addictive qualities.

Tianeptine

Tianeptine can be more potent than morphine and addictive opioids. (iStock)

Misuse of tianeptine can cause severe adverse health effects, including respiratory depression, severe sedation and death, according to the Drug Enforcement Administration.

Some companies market the drug as an aid for pain, anxiety and depression, or as a means of improving mental alertness in a pill, powder, salt or liquid form.

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The products are typically sold at convenience stores, gas stations, vape shops and online retailers, and go by names like Tianaa, ZaZa, Neptune’s Fix, Pegasus and TD Red.

people in line at gas station counter

Connecticut is the fifteenth state to classify tianeptine as a Schedule I controlled substance. (Markus Scholz/picture alliance via Getty Images)

Connecticut Lieutenant Governor Susan Bysiewicz said in a press release that the schedule change is a necessary step to combat addiction.

"With false marketing that led consumers to believe these are safe products, and with candy-like flavor options, these substances posed a clear threat to those battling substance-use disorder and our youngest residents," she added.

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The Nutmeg State also added Mitragyna speciosa (kratom), 7 hydroxymitragynine, Bromazolam, Flubromazolam, Nitazenes and Phenibut to the schedule classification.

Earlier this month, FDA Commissioner Martin Makary penned a letter sounding the alarm on what he called a "dangerous and growing health trend."

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"I am very concerned," Makary wrote. "I want the public to be especially aware of this dangerous product and the serious and continuing risk it poses to America’s youth."

New York-based Robert Schwaner, M.D., vice chair of system clinical affairs at Stony Brook Emergency Medicine, told Fox News Digital that the FDA has never approved tianeptine as a dietary supplement.

Tianeptine

"As with heroin and other opioids, significant mu-opioid receptor stimulation ultimately results in a loss of respiratory drive and subsequent cardiac arrest." (Dekalb County Sheriff's Office)

"The euphoria at low doses is primarily due to increased serotonergic activity from its serotonin reuptake effects. With increasing doses, the mu-opioid receptor stimulation may become lethal," said Schwaner. "As with heroin and other opioids, significant mu-opioid receptor stimulation ultimately results in a loss of respiratory drive and subsequent cardiac arrest."

Schwaner said he believes the substance requires national regulation due to its addictive qualities. 

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"Acting at the same receptor as opioids, tianeptine has the potential for an individual to develop tolerance, subsequent dependence and withdrawal from its use," he cautioned.

Fox News Digital reached out to the FDA for comment. 

Fox News Digital’s Greg Wehner and Melissa Rudy contributed to this report.