<unk>   (INN: diacetylmorphine, BAN: diamorphine) is a semi-synthetic opioid synthesized from morphine, a derivative of the opium poppy. It is the 3, 6-diacetyl ester of morphine <unk> ence diacetylmorphine). The white crystalline form is commonly the<unk> ydrochloride salt diacetylmorphine<unk> ydrochloride.
As with other opiates,<unk>  is used both as a pain-killer and a recreational drug.
One of the most common methods of<unk>  use is via intravenous injection. When taken orally,<unk>  undergoes extensive first-pass metabolism via deacetylation, making it a prodrug for the systemic delivery of morphine. When the drug is injected,<unk> owever, it avoids this first-pass effect, very rapidly crossing the blood-brain barrier due to the presence of the acetyl groups, which render it much more lipid-soluble than morphine itself. Once in the brain, it is deacetylated into 3- and 6-monoacetylmorphine and morphine, which bind to μ-opioid receptors resulting in intense euphoria with the feeling centered in the gut.
Frequent administration<unk> as a<unk> igh potential for causing addiction and may quickly lead to tolerance. If a continual, sustained use of<unk>  for as little as three days is stopped abruptly, withdrawal symptoms can appear. This is much shorter than the withdrawal effects experienced from other common painkillers such as oxycodone and<unk> ydrocodone.
Internationally,<unk>  is controlled under Schedules I and IV of the Single Convention on Narcotic Drugs. It is illegal to manufacture, possess, or sell<unk>  in the United States and the UK.<unk> owever, under the name diamorphine,<unk>  is a legal prescription drug in the United Kingdom. Popular street names for<unk>  include black tar, smack, junk, skag,<unk> orse, brain, chaw, chiva, and others. These are specific references to<unk>  and not used to describe any other drug.  Dope could be used to refer to<unk> , but may also indicate other drugs, from laudanum a century ago to nearly any contemporary recreational drug.
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