Dihydrocodeine elimination

Approximately one-third of both dihydrocodeine and tramadol are eliminated by the kidneys. Manufacturer s data for tramadol suggest that in hepatic or renal impairment the increase in half-life should be relatively low as long as one of these organs is functioning normally [48]. 

Treatment of 14-hydroxydihydrocodeine-B with thionyl chloride results only in chlorination of the aromatic nucleus (cf. the corresponding reaction with the four dihydrocodeine isomers, Chap. IV), but treatment with phosphorus pentachloride affords 14-hydroxy-6-chlorodihydrocodide [xrx], That the hydroxyl group at C-6 is the one that is replaced by chlorine is revealed by the fact that reduction of [xrx] by sodium amalgam and alcohol is attended by rupture of the cyclic ether link, giving 14-hydroxydihydrodesoxycodeine-C [xx], which is readily reduced catalytically to 14-hydroxytetrahydrodesoxy-codeine [xm]. All attempts to reduce [xrx] to a non-phenolic base, or to secure elimination of hydrogen chloride with production of a substance of the desoxycodeine-C type failed [6]. 

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