Opioid metabolites

Dihydromorphine (Paramorfan, Paramorphan) is a semi-synthetic opioid structurally related to and derived from morphine. The 7,8-double bond in morphine is reduced to a single bond to get dihydromorphine. Dihydromorphine is a moderately strong analgesic and is used clinically in the treatment of pain and also is an active metabolite of the analgesic opioid drug dihydrocodeine. Dihydromorphine occurs in trace quantities in assays of opium on occasion, as does dihydrocodeine, dihydrothebaine, tetrahydrothebaine, etc. The process for manufacturing dihydromorphine from morphine for pharmaceutical u

Norcodeine is an opiate analogue that is the N-demethylated derivative of codeine. It has relatively little opioid activity in its own right, but is formed as a metabolite of codeine following ingestion.

6-Monoacetylmorphine (6-MAM, 6-acetylmorphine, or 6-AM) is an opioid and also one of three active metabolites of heroin (diacetylmorphine), the others being morphine and the much less active 3-monoacetylmorphine (3-MAM).

Normorphine is an opiate analogue, the N-demethylated derivative of morphine, that was first described in the 1950s when a large group of N-substituted morphine analogues were characterized for activity. The compound has relatively little opioid activity in its own right, but is a useful intermediate which can be used to produce both opioid antagonists such as nalorphine, and also potent opioid agonists such as N-phenethylnormorphine. with its formation from morphine catalyzed by the liver enzymes CYP3A4 and CYP2C8.

Morphine-6-glucuronide (M6G) is a major active metabolite of morphine. M6G is formed from morphine by the enzyme UGT2B7. It has analgesic effects roughly half that of morphine. M6G can accumulate to toxic levels in kidney failure.

Morphine-3-glucuronide is a metabolite of morphine produced by UGT2B7. It is not active as an opioid agonist, but does have some action as a convulsant, which does not appear to be mediated through opioid receptors, but rather through interaction with glycine and/or GABA receptors. As a polar compound, it has a limited ability to cross the blood–brain barrier, but kidney failure may lead to its accumulation and result in seizures. Probenecid and inhibitors of P-glycoprotein can enhance uptake of morphine-3-glucuronide and, to a lesser extent, morphine-6-glucuronide. Reported side effects relat

Desmetramadol (), also known as '''O-desmethyltramadol (O-DSMT'''), is an opioid analgesic and the main active metabolite of tramadol. Tramadol is demethylated by the liver enzyme CYP2D6 to desmetramadol in the same way as codeine, and so similarly to the variation in effects seen with codeine, individuals who have a less active form of CYP2D6 will tend to have reduced analgesic effects from tramadol. Because desmetramadol itself does not need to be metabolized to induce an analgesic effect, it can be used in individuals with CYP2D6 inactivating mutations.

'Morphine-N-oxide (genomorphine') is an active opioid metabolite of morphine. Morphine itself, in trials with rats, is 11–22 times more potent than morphine-N-oxide subcutaneously and 39–89 times more potent intraperitoneally. However, pretreatment with amiphenazole or tacrine increases the potency of morphine-N-oxide in relation to morphine (intraperitoneally more so than in subcutaneous administration). A possible explanation is that morphine-N-oxide is rapidly inactivated in the liver and impairment of inactivation processes or enzymes increases functionality.

Norpethidine (normeperidine, pethidine intermediate B) is a 4-phenylpiperidine derivative that is both a precursor to, and the toxic metabolite of, pethidine (meperidine). It is scheduled by UN Single Convention on Narcotic Drugs. It is a Schedule II Narcotic controlled substance in the United States and has an ACSCN of 9233. The 2014 annual manufacturing quota was .

6-Monoacetylcodeine (6-MAC) is an acetate ester of codeine in which the hydroxyl group on the 6 position has been acetylated. It is occasionally present as an impurity in street heroin and is typically created when attempting to create heroin from a solution of morphine in which some of the codeine from the original opium solution still remains. It is formed either through the addition of acetic anhydride, which can only acetylate the 6 position on the codeine or as a result of the addition of acetic acid with a catalyst in an attempt to create 6-monoacetylmorphine, the equivalent ester of mor

Norpropoxyphene is a major metabolite of the opioid analgesic drug dextropropoxyphene, and is responsible for many of the side effects associated with use of this drug, especially the unusual toxicity seen during dextropropoxyphene overdose. It has weaker analgesic effects than dextropropoxyphene itself, but is a relatively potent pro-convulsant and blocker of sodium and potassium channels, particularly in heart tissue, which produces prolonged intracardiac conduction time and can lead to heart failure following even relatively minor overdoses. The toxicity of this metabolite makes dextropropo

Codeine-6-glucuronide (C6G) is a major active metabolite of codeine and may be responsible for as much as 60% of the analgesic effects of codeine. C6G exhibits decreased immunosuppressive effects compared to codeine. During its metabolism, codeine is conjugated with glucuronic acid by the enzyme UDP-Glucuronosyltransferase-2B7 (UGT2B7) to form codeine-6-glucuronide.

3-Monoacetylmorphine (3-MAM) or 3-acetylmorphine is a less active metabolite of heroin (diacetylmorphine), the other two being morphine and more active 6-monoacetylmorphine (6-MAM).

Norfentanyl is an inactive synthetic opioid analgesic drug precursor. It is an analog and metabolite of fentanyl with the removal of the phenethyl moiety (or functional group) from fentanyl chemical structure.