Phenadoxone

Phenadoxone (Heptalgin®, Heptazone) is an opioid analgesic of the open chain class (methadone and relatives) invented in Germany in 1947. It is one of a handful of useful synthetic analgesics which were used in the United States for various lengths of time in the 20 or so years after the end of the Second World War but which were withdrawn from the market for various or no known reason and which now are mostly in Schedule I of the United States' Controlled Substances Act of 1970, or (like phenazocine and bezitramide) in Schedule II but not produced or marketed in the US. Others on this list are ketobemidone (Ketogin®), dextromoramide (Dimorlin®, Palfium® and others), phenazocine (Narphen® and Prinadol®), dipipanone (Diconal®, Pipadone® and Wellconal®), piminodine (Alvodine®), propiram (Algeril®), anileridine (Leritine®) and alphaprodine (Nisentil®).

Phenadoxone is generally considered to be a strong opioid analgesic and is regulated in much the same way as morphine where it is used. The usual starting dose is 10-20 mg and it has a duration of analgesic effect of 1 to 4 hours. By comparison, methadone has an analgesic effect lasting from 3 to 6 hours although for use in opioid maintenance the dose is different from that used for analgesia and the sought effect of suppressing withdrawal symptoms and part of the rush of heroin can last for 24 to 72 hours. Phenadoxone is not used at this time for purposes other than pain relief.

Worldwide consumption of phenadoxone has actually increased slightly in recent years according a recent report from the World Health Organisation. Like its drug subcategory prototype methadone, phenadoxone can be used as the opioid analgesic in Brompton Mixture, aka Brompton cocktail. Phenadoxone is most used at the current time in Denmark and various countries in eastern Europe.