<unk>  is an analgesic in the opioid category, patented in 1955 and manufactured by Eli Lilly and Company.  It is an optical isomer of levopropoxyphene. It is intended to treat mild pain and also has antitussive (cough suppressant) and local anaesthetic effects. The drug has been taken off the market in Europe and the US due to concerns of fatal overdoses and heart arrhythmias. Its onset of analgesia (pain relief) is said to be 20–30 minutes and peak effects are seen about 1.5–2 hours after oral administration.<unk>  is sometimes combined with paracetamol or aspirin. Trade names include Darvocet-N and Di-Gesic, Darvon with APAP (for<unk>  and paracetamol) and Darvon with ASA (for<unk>  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paracetamol/dextropropoxyphene preparation is "co-proxamol" (sold under a variety of brand names); however, it has been withdrawn since 2007, and is no longer available to new patients, with exceptions. The paracetamol combination(s) are known as Capadex or Di-Gesic in Australia, Lentogesic in South Africa, and Di-Antalvic in France (unlike co-proxamol, which is an approved name, these are all brand names).<unk>  is known under several synonyms, including:
Alpha-d-4-dimethylamino-3-methyl-1,2-diphenyl-2-butanol propionate
[(2S,3S)-4-(Dimethylamino)-3- methyl-1,2-diphenylbutan-2-yl] propanoate
(+)-1,2-Diphenyl-2-propionoxy- 3-methyl-4-di-methylaminobutane
Desoxypropiophen
Dextropropoxyphene
Norpropoxyphene
Oxypertine
Methylergonovine 
Pixantrone
Mebhydrolin
Dexbrompheniramine
Cyclobutyrol