Observations placeholder

Dextropropoxyphene   is an analgesic intended to treat mild pain. It  is sometimes combined with paracetamol or aspirin. Trade-names include Darvocet-N  and Di-Gesic,  Darvon with APAP for dextropropoxyphene and paracetamol and Darvon with ASA for dextropropoxyphene and aspirin.   The British Approved Name (i.e. the generic name of the active ingredient) of the paracetamol/dextropropoxyphene preparation is co-proxamol (sold under a variety of brand names).   The paracetamol combination(s) are also known as Capadex or Di-Gesic, Lentogesic, and Di-Antalvic

Dextropropoxyphene acts as a 

• mu-opioid receptor agonist – giving the side effects shown earlier
• a potent, noncompetitive ₄ neuronal nicotinic acetylcholine receptor antagonist – which means it should act as a vasodilator
• as well as weak serotonin reuptake inhibitor.

 Which is an odd combination to say the least.   It was taken off the market in Europe and the US in 2007 due to concerns of fatal overdoses and arrhythmias. An estimated 10 million patients have used these products.   Some of the fatalities have been caused by over dose of the paracetamol (acetaminophen) in these products. The amount of dextropropoxyphene per tablet in the combination dextropoxyphene/acetaminophen (paracetamol) is relatively low (30–40 mg). If the person ‘over doses’, the paracetamol can reach liver toxic levels. This drug has been used by seriously ill people to end their lives. It is also responsible for some near death experiences. The slang name for the combination of this and other drugs used for suicide is the  "Darvon cocktail".  The FDA banned all sale of Darvon and Darvocet in 2010.  Many other countries have done likewise. Despite this it is still being prescribed by doctors.

A number of other drugs are analogues, derived from or related to this one: 

• Dimenoxadol (Estocin) is related to dextropropoxyphene
• Dioxaphetyl butyrate (trade names Amidalgon, Spasmoxal)
• Levacetylmethadol  -  levomethadyl acetate, Orlaam (trade name) or levo-?-acetylmethadol (LAAM) is similar in structure to methadone. It was approved in 1993 by the U.S. Food and Drug Administration for use in the treatment of opioid dependence. In 2001, Orlaam was removed from the European market due to reports of life threatening ventricular rhythm disorders In 2003, Roxane Laboratories, Inc. discontinued Orlaam in the US (LAAM)
• Lefetamine (Santenol) is a drug which is both a stimulant and an analgesic It was invented in the 1940s and was widely abused in Japan during the 1950s. It has been researched for medicinal use but showed little advantage over other analgesics. More recently it has been abused in Europe, but it remains an obscure drug on the illicit market.  It binds to opioid receptors and also works as norepinephrine-dopamine reuptake inhibitor.
• Norpropoxyphene is a major metabolite of dextropropoxyphene and is responsible for many of the side effects associated with use of this drug, especially the unusual toxicity seen during dextropropoxyphene overdose.  It can lead to heart failure following even relatively minor overdoses.  The toxicity of this metabolite makes dextropropoxyphene up to 10 times more likely to cause death following overdose compared to other similar mild opioid analgesics.