The New Synthetics – Fentanyl and Carfentanil
The opioid fentanyl was first synthesized in 1960 by Belgium researcher, Paul Janssen. This drug and a number of structural analogues, including sufentanil, lofentanil and carfentanil were found to have a strong agonist effect on the opioid receptors in the brain and were immediately recognized as powerful analgesics. Fentanyl, the first to be marketed commercially as an analgesic is ~ 100x more potent than morphine, carfentanil, developed to sedate large animals, 10,000x more potent. In 1984, the Food and Drug Administration (FDA) declared all fentanyl analogues to be Schedule I substances (completely illegal and useless for medical purposes).
Fig 10.3 Schematic representation of the varying potency of different opioids
Fentanyl is a powerful fast-acting opioid prescribed for the control of strong pain. It is rapidly metabolised in the body by the (Cytochrome P450) liver enzyme and excreted. Indeed, this rapid breakdown of the drug means that the dug can sometimes be difficult to detect at post mortem. The oral ingestion of the drug results in lower plasma than that obtained by other available means of the drug’s administration (transdermal, intravenous, buccal, or even as an aerosol (as used in 2002 in the Russian theatre hostage crisis, see: http://rense.com/general31/opi.htm