3-Methylfentanyl (3-MF, mefentanyl) is an opioid analgesic that is an analogue of fentanyl. 3-Methylfentanyl is one of the most potent drugs that has been widely sold on the black market,
α-methylfentanyl was invented in 1976 and appeared on the black market under the name "China White". It was first identified in the bodies of two drug overdose victims in Orange County, California, in December 1979, who appeared to have died from opiate overdose but tested negative for any known drugs of this type.
Para-fluorofentanyl was sold briefly on the black market in the early 1980s, before the introduction of the Federal Analog Act which for the first time attempted to control entire families of drugs based on their structural similarity rather than scheduling each drug individually as they appeared.
MPPP (1-methyl-4-phenyl-4-propionoxypiperidine, Desmethylprodine) is an opioid analgesic drug. It is not used in clinical practice, but has been illegally manufactured for recreational drug use. It is an analog of pethidine (Demerol), but since it is not used in medicine, the DEA has labeled it a Schedule I drug in the United States.