Potentially addictive substance sold at gas stations, smoke shops

What's known on the streets as gas station heroin -- which is just one of its names -- is legal in Maryland for anyone to buy, and there's a good chance it's sold at a smoke shop or gas station near you. It goes by many names -- Tianna, Pegasus, Zaza -- and it's easy to buy. In high doses, it can be dangerous. The substance, tianeptine, is sold as a supplement to help with anxiety and depression, but as a Maryland family found out, it can be very addictive.