Fentanyl was first prepared and developed by Dr. Paul Janssen in 1959 under a patent held by his company Janssen Pharmaceutica.
As a potent analgesic that is almost a hundrend times stronger then morphine, the use of fentanyl as a pain reliever and anesthetic was quickly adopted in the medical setting. In the 1960s, the agent was introduced as an intravenous anesthetic under the brand name Sublimaze.
Following the popularity of Sublimaze, analogues of fentanyl were developed and included Sufentanil, Alfentanil, Lofentanil and Remifentanil.
By the mid 1990s the fentanyl patch was developed, which could deliver the drug to a patient transdermally. The Duragesic patch could be worn on the skin and was useful in the management of chronic pain felt by patients with cancer, for example. The patch was made of an inert alcohol gel infused with pre-determined doses of fentanyl. The drug is released by the patch into the body fats, from where it slowly moves into the bloodstream over two or three days, therefore providing long-term pain relief. Duragesic patches underwent several clinical trials, after which they were introduced and popularized in clinical practice.
Next, other delivery devices were developed with examples including the Fentora buccal tablets and the Actiq lollipop. These oral preparations contained fentanyl citrate mixed with fillers. Actiq provided fast-acting relief of breakthrough pain in long-term pain sufferers. Further fentanyl products included an effervescent lozenge and a buccal spray. Despite the various different modes of delivery that were introduced, the transdermal skin patches remain the most widely used form of fentanyl delivery.
More recently, another fentanyl product that has been approved by the US food and Drug Administration (FDA) for breakthrough pain is Onsolis. Here, a soluble film of fentanyl on a disc can be placed in the mouth and absorbed, which avoids the possibility of inhalation or crushing.
Reviewed by Sally Robertson, BSc