Heroin is a crude preparation of diamorphine. It is a semisynthetic product obtained by acetylation of morphine, which occurs as a natural product in opium: the dried latex of certain poppy species (e.g. Papaver somniferum L.). Diamorphine is a narcotic analgesic used in the treatment of severe pain. Illicit heroin may be smoked or solubilised with a weak acid and injected. Whereas opium has been smoked since historical times, diamorphine was first synthesised in the late nineteenth century. Heroin is under international control.


Molecular structure (1)

Molecular formula: C21H23NO5
Molecular weight: 369.4 g/mol

Diamorphine (diacetylmorphine; CAS-561-27-3) is produced by the acetylation of crude morphine. The systematic name (IUPAC) is (5α,6α)-7,8-didehydro-4,5-epoxy-17-methylmorphinan-3,6-diol acetate. Although five pairs of enantiomers are theoretically possible in morphine, only one occurs naturally (5R, 6S, 9R, 13S, 14R).

(1) Diacetylmorphine: the principal psychoactive constituent of heroin

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Physical form


Copyright TICTAC Communications Ltd 2006. This picture has been kindly provided by the UK National focal point.

South-west Asian heroin is a brown powder usually in the form of the free base, which is insoluble in water but soluble in organic solvents. The less common south-east Asian heroin is usually a white powder in the form of the hydrate hydrochloride salt (CAS-1502-95-0), which is soluble in water but insoluble in organic solvents.

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Diamorphine, like morphine and many other opioids, produces analgesia. It behaves as an agonist at a complex group of receptors (the μ, κ and δ subtypes) that are normally acted upon by endogenous peptides known as endorphins. Apart from analgesia, diamorphine produces drowsiness, euphoria and a sense of detachment. Negative effects include respiratory depression, nausea and vomiting, decreased motility in the gastrointestinal tract, suppression of the cough reflex and hypothermia. Tolerance and physical dependence occur on repeated use. Cessation of use in tolerant subjects leads to characteristic withdrawal symptoms. Subjective effects following injection are known as ‘the rush’ and are associated with feelings of warmth and pleasure, followed by a longer period of sedation. Diamorphine is 2–3 times more potent than morphine. The estimated minimum lethal dose is 200 mg, but addicts may be able to tolerate ten times as much. Following injection, diamorphine crosses the blood–brain barrier within 20 seconds, with almost 70 % of the dose reaching the brain. It is difficult to detect in blood because of rapid hydrolysis to 6-monoacetylmorphine and slower conversion to morphine, the main active metabolite. The plasma half-life of diamorphine is about three minutes. Morphine is excreted in the urine largely as the glucuronide conjugate. Diamorphine is associated with far more accidental overdoses and fatal poisonings than any other scheduled substance. Much morbidity is caused by infectious agents transmitted by unhygienic injection.

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The latex from the seed capsules of the opium poppy (Papaver somniferum L.) is allowed to dry. This material (opium) is dispersed in an aqueous solution of calcium hydroxide (slaked lime). The alkalinity is adjusted by adding ammonium chloride, causing morphine base to precipitate. The separated morphine is boiled with acetic anhydride. Sodium carbonate is added, causing the crude diamorphine base to separate. Depending on the region, this may be used directly, further purified or converted into the hydrochloride salt.

Until the late 1970s, nearly all heroin consumed in Europe came from south-east Asia, but now most originates from south-west Asia, an area centred on Afghanistan and Pakistan. Heroin is also produced in certain parts of South America, but that material is rarely seen in Europe. Acetic anhydride, an essential precursor in the manufacture of heroin, is listed in Table I of the United Nations 1988 Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. The corresponding EU legislation is set out in Council Regulation (EEC) No 3677/90 (as later amended), which governs trade between the EU and third countries. As with other naturally occurring drugs of misuse (e.g. cocaine and cannabis), total synthesis of the active principles is not currently an economic proposition.

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Mode of use

Heroin from south-west Asia may be ‘smoked’ by heating the solid on a metal foil above a small flame and inhaling the vapour. Those intending to inject this form of heroin must first solubilise it with, for example, citric acid or ascorbic acid. Heroin from south-east Asia is suitable for direct injection of a solution. A typical dose is 100 mg at street level purity. Except when used therapeutically as an analgesic drug, ingestion of diamorphine/heroin is a much less effective route of administration.

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Other names

A large number of street terms are in use, including horse, smack, shit and brown.

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In common with many other opioids, the Marquis field test produces a violet/purple coloration. In the mass spectrum, the major ions are m/z = 327, 43, 369, 268, 310, 42, 215 and 204. Using gas chromatography, the limit of detection of both diamorphine and 6-monoacetylmorphine is 100 μg/L.

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Typical purities

Apart from diamorphine, heroin contains variable amounts of other opium alkaloids and acetylated alkaloids (e.g. noscapine, papaverine and acetylcodeine) as well as adulterants such as caffeine and paracetamol. It is believed that the latter are added to heroin either at the time of manufacture or during transit. Other less common psychoactive adulterants include phenobarbitone, methaqualone and diazepam. The hydrolysis product (6-monoacetylmorphine) may also be present and arises when heroin is stored in damp conditions or in non-acidified aqueous solutions. The free base constitutes 87.2 % of the hydrate hydrochloride salt.  

In 2011, the mean purity of brown heroin at street level in Europe varied considerably (between 5.8 % (Austria) and 43.6 % (Turkey)). The mean purity of white heroin was generally higher (14 % in Austria and 43 % in Norway) in the five European countries reporting data (Table PPP-6 part (i)).

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Control status

Heroin is listed in Schedule I of the United Nations 1961 Single Convention on Narcotic Drugs. Diamorphine is also included in a generic sense since the 1972 Protocol, which revised the 1961 Convention, extended control to esters and ethers of scheduled substances. Thus, diamorphine is the diacetyl ester of morphine (Schedule 1).

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Estimates for last year prevalence of heroin use among young adults (15- to 34-year-olds) in the general population range between 0.0 % and 0.7 %. However, due to the very low figures reported and the hidden nature of heroin use, general population surveys are not considered robust means for monitoring use of this substance. Therefore, indirect statistical extrapolations, based on patterns of contact with data sources, where part of this population is observed, are used to understand the prevalence of this phenomenon.

The average prevalence of problem/high-risk opioid use among adults (15–64) is estimated at 0.41 %, the equivalent of 1.4 million problem opioid users in Europe in 2011. In Europe, prevalence estimates of problem opioid use vary between less than one and more than seven cases per 1 000 population aged 15–64 (Table PDU-1 part (iii)). 'Opioids' here include mainly heroin, however, there are countries, where significant numbers of users of other opioids exist, for example Finland (buprenorphine) or Estonia (fentanyl).

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Street price

In 2011 the mean retail price of brown heroin continued to be higher in Nordic countries than the rest of Europe and ranged between EUR 24 (Bulgaria) and EUR 143 (Sweden) per gram. The price of white heroin is reported only by a few European countries and ranged between EUR 62.7 (Italy) and EUR 249 (Sweden) per gram (Table PPP-2, part (i)).

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Medical use

Diamorphine is a narcotic analgesic with limited use in the treatment of severe pain.

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Cooper, D. A. (1989), ‘Clandestine production processes for cocaine and heroin’, in: Klein, M., Sapienza, F., McClain, H. and Khan, I. (eds.) Clandestinely produced drugs, analogues and precursors: problems and solutions, United States Department of Justice Drug Enforcement Administration, Washington, DC.

King, L. A. and McDermott, S. (2004), ‘Drugs of abuse’, in: Moffat, A. C., Osselton, M. D. and Widdop, B. (eds.), Clarke's analysis of drugs and poisons, 3rd edn, Vol. 1, pp. 37–52, Pharmaceutical Press, London.

Moffat, A. C., Osselton, M, D. and Widdop, B, (eds.) (2004), Clarke's analysis of drugs and poisons, 3rd edn, Vol. 2, Pharmaceutical Press, London.

Schiff, P. L. (2002), ‘Opium and its alkaloids’, American Journal of Pharmaceutical Education 66, pp. 186–194.

United Nations (2006), Multilingual Dictionary of Narcotic Drugs and Psychotropic Substances under International Control, United Nations, New York.

United Nations Office on Drugs and Crime (2004), World Drug Report 2004, Vol. 1: Analysis, United Nations Office on Drugs and Crime, Vienna (http://www.unodc.org/pdf/WDR_2004/volume_1.pdf).

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Further reading

The following publications have been proposed for further reading by Reitox national focal points. They represent a shortlist of key publications on the drug in each Member State*.

Neto, D. (1995), Tratamento combinado e por etapas de heroinodependentes : características e evolução de uma amostra, Domingos Neto, Lisboa.

Foundation for Community Care (2004), Heroin addiction: after-care a key factor in rebuilding a life free of drugs, PHARE 2004 project.

Lovrečič, M. (2006), Problematika nevropsihofarmakoterapije zasvojenih s heroinom s pridruženo duševno motnjo (Problems of neuropsychopharmacotherapy in heroin addicts with psychiatric comorbidity), Univerza v Ljubljani, Medicinska fakulteta, Ljubljana.

Lovrečič B. (2004), Uporaba in posledice uporabe heroina pri odvisnikih (Use and consequences of heroin use in addicted persons), Medicinska fakulteta, Ljubljana.

Anneli Uusküla, et al. (2005), The prevalence of injecting drug use in Estonia 2004, Tervise Arengu Insituut, Tallinn.

Miranda, J. J. F. and Melich, M. T. (2005), Monografia Opiáceos, Adicciones Vol. 17, suplemento 2.


Vasconcelos, L. A. (2003), Heroína: Lisboa como território psicotrópico nos anos noventa, Instituto de Ciências Sociais da UL, Lisboa.

Maremmani, I., Pacini, M., Lubrano, S., Lovrečič, M. and Pertugi, G. (2003), ‘Dual diagnosis heroin addicts: the clinical and therapeutic aspects’, in: Heroin Addict Related Clinical problems 5(2): pp. 7–98.

Svensson, B. (2005), Heroinmissbruk (Heroin dependence), Studentlitteratur, Lund.

Lalander, P. (2001), Hela världen är din: en bok om unga heroinister, Studentlitteratur, Lund.

Antoniusson, E.-M. (2005), Överdos: heroinets fallgrop, Studentlitteratur, Lund.

* Please note that not all national focal points have provided references so the list above cannot be considered exhaustive. Moreover, inclusion in this list does not imply that the EMCDDA endorses these publications. The views expressed in these publications are those of the authors and do not necessarily reflect those of the EMCDDA.

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Page last updated: Wednesday, 08 May 2013