Heroin is one of a group of drugs known as "opiates". Other opiates include opium, morphine, codeine, pethidine, oxycodone, buprenorphine and methadone. Heroin and other opiates are depressants. Depressants do not necessarily make you feel depressed. Rather, they slow down the activity of the central nervous system and messages going between the brain and the body.
Heroin is known by a variety of other names, including: horse, hammer, H, dope, smack, junk, gear and boy.