Methyldihydromorphine is a semi-synthetic opioid

Opioid

An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

 drug developed in Germany in 1936, controlled under both domestic law and UN conventions because of its possible potential for abuse. Methyldihydromorphine is related to heterocodeine

Heterocodeine

Heterocodeine is an opiate derivative, the 6-methyl ether of morphine, and a structural isomer of codeine. Heterocodeine was first synthesised in 1932, and can be made from morphine by selective methylation. Codeine is the natural mono-methyl ester, so methylated where it must be metabolized to...

 and is not a synonym for dihydrocodeine

Dihydrocodeine

Dihydrocodeine, also called DHC, Drocode, Paracodeine and Parzone and known by the brand names of Synalgos DC, Panlor DC, Panlor SS, Contugesic, New Bron Solution-ACE, Huscode, Drocode, Paracodin, Codidol, Didor Continus, Dicogesic, Codhydrine, Dekacodin, DH-Codeine,...

, and its structure suggests that it is six to nine times stronger than morphine and 72 times stronger than dihydrocodeine

Dihydrocodeine

Dihydrocodeine, also called DHC, Drocode, Paracodeine and Parzone and known by the brand names of Synalgos DC, Panlor DC, Panlor SS, Contugesic, New Bron Solution-ACE, Huscode, Drocode, Paracodin, Codidol, Didor Continus, Dicogesic, Codhydrine, Dekacodin, DH-Codeine,...

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