Heterocodeine is an opiate

Opiate

In medicine, the term opiate describes any of the narcotic opioid alkaloids found as natural products in the opium poppy plant.-Overview:Opiates are so named because they are constituents or derivatives of constituents found in opium, which is processed from the latex sap of the opium poppy,...

 derivative, the 6-methyl ether

Ether

Ethers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...

 of morphine

Morphine

Morphine is a potent opiate analgesic medication and is considered to be the prototypical opioid. It was first isolated in 1804 by Friedrich Sertürner, first distributed by same in 1817, and first commercially sold by Merck in 1827, which at the time was a single small chemists' shop. It was more...

, and a structural

Chemical structure

A chemical structure includes molecular geometry, electronic structure and crystal structure of molecules. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together. Molecular geometry can range from the very simple, such as...

 isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

 of codeine

Codeine

Codeine or 3-methylmorphine is an opiate used for its analgesic, antitussive, and antidiarrheal properties...

. 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 activate, and thus acting as a prodrug. Functionality contrasting this 6-position (semi-)synthetic mono-methyl ether, heterocodeine, which is a direct agonist: named "hetero-" for being the isomeric reverse oriented partner to codeine.

Heterocodeine is 6 times more potent than morphine due to having a substitution at the 6-hydroxy position, in a similar manner to 6-acetylmorphine. The drug methyldihydromorphine

Methyldihydromorphine

Methyldihydromorphine is a semi-synthetic opioid drug developed in Germany in 1936, controlled under both domestic law and UN conventions because of its possible potential for abuse...

 (dihydroheterocodeine) is a derivative of heterocodeine. As noted about the morphine metabolite morphine-6-glucuronide

Morphine-6-glucuronide

Morphine-6-glucuronide is a major active metabolite of morphine, and as such is the molecule responsible for much of the pain-relieving effects of morphine . M6G is formed from morphine by the enzyme UDP-Glucuronosyltransferase-2B7...

, 6-position esters of morphine bind to the otherwise unagonized human mu receptor subtype mu-3 (or μ3), this includes, beside the 6-acetylmorphine metabolite of heroin, heterocodeine.