Propoxyphene ( a withdrawal drugs)
Propoxyphene or known as Darvon is a pain reliever (analgesic) that works as effective as narcotics analgesic like morphine yet lower in abuse liability 1; 2 . It first introduced in 1957 and became popularly prescribed drug along with aspirin to soothe mild to moderate pain in the patients. In 2004 it was the 12 th bestselling generic drug in the US market 1; 3; 4 . Mostly propoxyphene was prescribed together with a nonsteroidal non-inflammatory drug (NSAIDs) like aspirin to enhance the analgesic effect. Both possesses similar efficacy through a different route of a mechanism. Aspirin inhibits the chemoreceptors in the peripheral nervous system while propoxyphene affects the central nervous system 3; 5 . As a group of narcotic drugs, propoxyphene binding in the opioid receptor, inhibit pain transmission. It is acted as an agonist of µ 1 (mu) opioid receptor and some κ (kappa) receptor, exerts an analgesic transmission. However, it also binds to µ 2 opioid receptor ...