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. 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 trace amounts in the brain of certain mammals. See also 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 References Acetate esters 4,5-Epoxymorphinans Heroin Opioid metabolites Morphine Mu-opioid receptor agonists Prodrugs Phenols Semisynthetic opioids