3-Methylfentanyl

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, estimated to be between 400-6000 times stronger than morphine depending on which isomer is used (with cis isomer being the more potent one).

3-Methylfentanyl was first discovered in 1974 and subsequently appeared on the street as an alternative to the clandestinely produced fentanyl analogue α-methylfentanyl. However it quickly became apparent that 3-methylfentanyl was much more potent than α-methylfentanyl, and corespondingly even more dangerous.

While 3-methylfentanyl was initially sold on the black market for only a short time between 1984-1985, its high potency made it an attractive target to clandestine drug producers, as racemic 3-MF is 10-15x more potent than fentanyl and so correspondingly larger amounts of cut product for street sales can be produced for an equivalent amount of effort as for producing fentanyl itself; one gram of 3-methylfentanyl might be sufficient to produce several thousand dosage units once diluted for sale. 3-MF has thus reappeared several times, at various places around the world, and is currently a problematic drug of abuse in Scandinavian and Eastern European countries such as Finland and Estonia

Other opioid analogues even more potent still than 3-MF are known, such as carfentanil and ohmefentanyl, but these are significantly more difficult to manufacture than 3-methylfentanyl and have not been so well accepted as street drugs.

3-Methylfentanyl has similar effects to fentanyl, but is far more potent due to increased binding affinity to its target site. Since fentanyl itself is already highly potent, 3-methylfentanyl is extremely dangerous when used recreationally, and has resulted in many deaths among opiate addicts using the drug. Side effects of fentanyl analogues are similar to those of fentanyl itself, which include itching, nausea and potentially serious respiratory depression which can be life-threatening.

3-Methylfentanyl was also reported by Russian media as the identity of the anaesthetic "gas" Kolokol-1 (actually an aerosol, of a free base dissolved in halothane) used in the Moscow theater hostage crisis in 2002, in which many hostages died from accidental overdoses of the narcotic.