Description

When the 4-phenyl substituent of meperidine was replaced with a 4-aniline with a nitrogen connection, the potency increased. This led to the development of the 4-anilidopiperidine series of compounds. Fentanyl (Sublimaze) was the first compound marketed and was found to be almost 500 times more potent than meperidine. The high lipophilicity of fentanyl gave it a quick onset, and the quick metabolism led to a short duration of action. The combination of potency, quick onset, and quick recovery led to the use of fentanyl as an adjunct anesthetic.