During the early 1960s, a powerful new form of opiate-based painkiller and intravenous anesthetic called fentanyl became generally available in the medical community. Fentanyl, also known by the trade names Duragesic® and Actiq®, was at least 80 times more potent than morphine, which limited its legal use to surgical anesthetic procedures and advanced pain management for cancer patients and others who could tolerate opiate-based painkillers. One form of fentanyl, Actiq®, was commonly administered as a oral lozenge or lollipop. This form of fentanyl is also known in the illegal drug world as a "perc-o-pop."

A perc-o-pop is no run-of-the-mill painkiller. Patients who are prescribed Actiq® lozenges or lollipops are generally in excruciating pain as a result of heart surgery or cancer treatments. Fentanyl is also administered through transdermal patches known by the trade name Duragesic® and is highly controlled by federal law. The street drug version of a perc-o-pop is quite often stolen from authorized pharmacies or directly from patients who depend on the lozenge or lollipop for pain management.

One reason a fentanyl perc-o-pop is such a popular street drug is the ease of administration. Users do not need elaborate drug kits filled with intravenous needles, glass pipes or butane torches. A perc-o-pop can simply be placed in the mouth and allowed to dissolve naturally. Fentanyl penetrates the blood/brain barrier exceptionally quickly, which means the effects can be felt within minutes of ingestion.

Perc-o-pops are also used as substitutes for heroin, which can be difficult to obtain on the street at times. The problem is that a perc-o-pop is much more potent than an average hit of heroin, which means overdoses from Fentanyl are a definite risk drug users face. Other forms of fentanyl, including the liquid contents of Duragesic® transdermal patches, can also be injected intravenously or held under the tongue much like a perc-o-pop.

Perc-o-pops also go by a number of other street drug names, such as Apache, China girl, China white, Dance fever, Friend, Goodfella, Jackpot, Murder 8, TNT, Tango and Cash and Lollipop.