Diacetylmorphine is a semi-synthetic opioid synthesized from morphine, a derivative of the opium poppy. It is more commonly known by its street name "heroin," but it is also sometimes referred to as "smack." Amphetamine, barbiturates, and crack are different types of drugs. Amphetamines are a type of stimulant, barbiturates are depressants, and crack is a form of cocaine that can be smoked.