heroin
n. a highly addictive opioid that is a synthetic analog of morphine and three times more potent. In many countries, including Great Britain and Canada, it is used clinically for pain management (see diacetylmorphine), but it is not legally available in the United States due to concerns about its potential for abuse. Its rapid onset of action leads to an intense initial high, followed by a period of euphoria and a sense of well-being. As a street drug, heroin is commonly injected intravenously or subcutaneously (called skin popping). Injection using shared needles is a common mechanism of transmission of HIV, hepatitis, and other diseases. It can also be ingested nasally (snorted) or smoked. See opioid intoxication; opioid use disorder; opioid withdrawal.