Designer drugs are made by underground chemists in order to create street drugs that are not specifically listed as controlled substances by the Drug Enforcement Administration. A designer drug is made by changing the molecular structure of an existing drug or drugs to create a new substance. An example is Ecstasy. The street names vary. Because unlicensed and untrained amateurs create them, these drugs can be extremely dangerous -- in many cases, more dangerous and potent than the original drug. Designer drugs derived from the pharmaceutical drug, fentanyl, have been associated with hundreds of unintentional deaths in the United States.
Drugs designed and synthesized, often for illegal street use, by modification of existing drug structures (e.g., amphetamines). Of special interest are MPTP (a reverse ester of meperidine), MDA (3,4-methylenedioxyamphetamine), and MDMA (3,4-methylenedioxymethamphetamine). Many drugs act on the aminergic system, the physiologically active biogenic amines.