I need to know what is propoxyphene?

Darvon: Propoxyphene is a synthetic "opioid, " a drug which acts at the same receptors as opium and its derivatives. It is closely related to methadone. The trade name in the us was darvon, and it commonly came together with tylenol (acetaminophen) as darvocet. It was taken off the market in the us in 2000, because it was not very effective as a pain reliever and could cause cardiac problems. It is still sold elsewhere.