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Systematic (IUPAC) name
Clinical data
Pharmacokinetic data
Half-life < 5 mins
2784-73-8 N
PubChem CID 5462507
ChemSpider 4575434 YesY
Synonyms 6-acetylmorphine
Chemical data
Formula C19H21NO4
327.374 g/mol
 N (what is this?)  (verify)

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

6-MAM is rapidly created from heroin in the body, and then is either metabolized into morphine or excreted in the urine. Since 6-MAM is a unique metabolite to heroin, its presence in the urine confirms that heroin was the opioid used. This is significant because on a urine immunoassay drug screen, the test typically tests for morphine, which is a metabolite of a number of legal and illegal opiates/opioids such as codeine, morphine sulfate, and heroin. Trace amounts of 6-MAM, a specific metabolite of heroin, are also excreted for approximately 6-8 hours following heroin use.[1] so a urine specimen must be collected soon after the last heroin use, however, the presence of 6-MAM suggests that heroin was used as recently as within the last day. 6-MAM is naturally found in the brain of certain mammals.[2]

Heroin is rapidly metabolized by esterase enzymes in the brain and has an extremely short half-life. It has also relatively weak affinity to μ-opioid receptors because the 3-hydroxy group which is essential for effective binding to the receptor is masked by the acetyl group. Therefore, heroin acts as a pro-drug, serving as a lipophilic transporter of sorts for the systemic delivery of morphine, which actively binds with μ-opioid receptors.[3][4]

6-MAM already has a free 3-hydroxy group and shares the high lipophilicity of heroin, so it penetrates the brain just as quickly and does not need to be deacetylated at the 6-position in order to be bioactivated; this makes 6-monoacetylmorphine somewhat more potent than heroin,[5] but it is rarely encountered as an illicit drug due to the difficulty in selectively acetylating morphine at the 6-position without also acetylating the 3-position. This can however be accomplished by using acetic acid with an appropriate catalyst to carry out the acetylation,{[1]} rather than acetic anhydride, as acetic acid is not a strong enough acetylating agent to acetylate the phenolic 3-hydroxy group but is able to acetylate the 6-hydroxy group, thus selectively producing 6-MAM rather than heroin. The process used in creating black tar heroin actually leaves 6-MAM in the final product, which is one of several reasons why black tar, even when less pure, may be more potent than some powder varieties of heroin.

See also[edit]

  • M3G, morphine-3-glucuronide an inactive metabolite of morphine much as 3-MAM is the less active metabolite of heroin (notably here as morphine is an active secondary metabolite of heroin itself with 6-Monoacetylmorphine being the intermediate stage)
  • M6G, morphine-6-glucuronide the active variant in close relation to 6-MAM, being relative as twin metabolites of this articles very metabolite itself, morphine, twinned to a metabolite (3-MAM) of a parent compound (heroin) of this article's chemical
Acetyl groups of heroin. In 6-MAM upper group is changed to hydrogen making hydroxyl-group in 3-position.


  1. ^ https://www.redwoodtoxicology.com/resources/drug_info/opiates
  2. ^ "6-Acetylmorphine: a natural product present in mammalian brain". Proc. Natl. Acad. Sci. U.S.A. 85 (14): 5335–8. July 1988. doi:10.1073/pnas.85.14.5335. PMC 281745. PMID 3393541. 
  3. ^ "Evidence from opiate binding studies that heroin acts through its metabolites". Life Sci. 33 Suppl 1: 773–6. 1983. doi:10.1016/0024-3205(83)90616-1. PMID 6319928. 
  4. ^ Ricerca Italiana - PRIN - Role of morphine glucuronides in heroin addiction
  5. ^ "Relative cataleptic potency of narcotic analgesics, including 3,6-dibutanoylmorphine and 6-monoacetylmorphine". Prog. Neuropsychopharmacol. Biol. Psychiatry 8 (4-6): 747–50. 1984. doi:10.1016/0278-5846(84)90051-4. PMID 6543399.