Heroin

Diacetylmorphine

Diamorphine, H, Smack, Junk, Brown

Psychoactive Class

Chemical Class

Heroin (diacetylmorphine¹) is a semi-synthetic opioid of the morphinan class derived from morphine¹, a natural product of the opium poppy¹. First synthesized by a British chemist in 1874¹ and later commercialized by Bayer in 1898², it is among the most notorious substances of abuse worldwide. Heroin is highly addictive³ and exists in forms ranging from white or brown powder to black tar⁴, with street purity varying dramatically from as low as 5% to as high as 95%.

Dosage & Duration

Dosage

Threshold5-5 mg

Light7.5-20 mg

Moderate20-35 mg

Strong35-50 mg

Heavy50+ mg

Duration

Onset10-60 seconds

Come Up10-60 seconds

Peak1-90 minutes

Offset1-3 hours

After Effects1.5-3 hours

Total3-7 hours

Subjective Effects

Effects vary widely by individual, dose, and context.

Physical

The physical effects of heroin can be broken down into several components which progressively intensify proportional to dosage.

Respiratory depression Itchiness Constipation Cough suppression Difficulty urinating Nausea Sedation Pupil constriction

Cognitive

The cognitive effects of heroin can be broken down into several components which progressively intensify proportional to dosage.

Anxiety suppression Compulsive redosing

Visual

Forked from Subjective Effect Documentation

by Josie KinsJuly 2015.

Reagent Testing

Loading reagent data

Expected colorimetric results are being prepared.

Pharmacology

Pharmacodynamics

Heroin (diamorphine) itself exhibits relatively low affinity for the μ-opioid receptor and functions primarily as a prodrug.¹ Its pharmacological effects are mediated through its active metabolites morphine and 6-monoacetylmorphine (6-MAM), both of which are μ-opioid receptor agonists.¹ Morphine additionally binds to δ- and κ-opioid receptors.¹ These opioid metabolites also decrease the inhibitory activity of GABAergic interneurons, resulting in increased dopamine release.¹ There is evidence that 6-MAM may bind to a distinct μ-opioid receptor subtype (mu-3), though the contribution of this receptor to heroin's overall pharmacology remains unknown.

Pharmacokinetics

Heroin undergoes rapid deacetylation by esterase enzymes, with a parent compound half-life of approximately two to three minutes.⁵¹ When taken orally, it is subject to extensive first-pass metabolism, yielding oral bioavailability below 35%.⁶ Deacetylation produces the active metabolites 6-monoacetylmorphine (6-MAM) and morphine, along with the inactive 3-monoacetylmorphine.¹ When injected, the acetyl groups confer lipophilicity that allows rapid crossing of the blood-brain barrier before central deacetylation occurs.⁵¹ The majority of the drug is excreted renally as glucuronides, with approximately 7 to 10% eliminated via the biliary system.⁵

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

AlcoholBenzodiazepinesCocaineDXMGHB/GBLKetamineMXEPregabalinTramadol

Unsafe

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

Diphenhydramine

Caution

Use caution

These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.

AmphetaminesMAOIsMephedroneNitrous oxidePCP

TripSit

Tolerance

Full Tolerance

With sustained repeated heroin use, many effects become less responsive. Tolerance does not develop at the same pace for every effect; constipation-related tolerance is especially slow compared with other effects. As a result, users may need progressively higher doses to obtain effects that previously occurred at lower doses.

Baseline Reset

1-2 weeks

Half Tolerance

3-7 days

Cross Tolerance

Opioids (all other opioid receptor agonists will have reduced effect after heroin consumption)

Harm Potential

Addiction & Dependence

Psychological

Extremely High

Heroin is considered extremely addictive with a high potential for abuse.⁷ The combination of powerful euphoric effects and rapid tolerance development leads many users to compulsive redosing and difficulty controlling their use. Psychological dependence can develop quickly, often accompanied by cravings and loss of interest in other activities.

Physical

High

Profound physical dependence develops with repeated use. Withdrawal symptoms may begin within 2-6 hours of the last dose and include sweating, anxiety, severe muscle and bone aches, nausea, vomiting, diarrhea, insomnia, and involuntary muscle spasms.⁸ While extremely unpleasant, opioid withdrawal is generally not life-threatening.⁸ Tolerance decreases significantly after periods of abstinence, making relapse particularly dangerous.⁸

Toxicity

Respiratory

Respiratory depression is the primary mechanism of overdose death; heavy doses suppress breathing proportionally to the amount consumed, potentially reducing breathing rate to 2-4 breaths per minute.

Central Nervous System

Repeated use alters brain structure and physiology, with studies showing some deterioration of white matter in chronic users; these changes may affect decision-making, behavior regulation, and stress responses.¹¹

Auditory

Heroin is known to be ototoxic, causing hearing loss, tinnitus, and balance issues; effects may persist long after use.¹²

Gastrointestinal

Constipation is a common and persistent effect with regular use, representing one of the few direct long-term complications of unadulterated heroin.

Urinary

Urinary retention and difficulty urinating can occur with chronic and repeated use.

Cardiovascular

Decreased heart rate and hypotension occur during intoxication; heroin use has been associated with myocardial infarction.¹³

Renal

Decreased kidney function (nephropathy) has been reported in intravenous users.¹⁵

Pulmonary

Heroin inhalation has rarely caused toxic leukoencephalopathy¹⁶¹⁷ and has been documented to cause severe acute asthma attacks or exacerbation of underlying asthma, potentially resulting in death.¹⁸¹⁹

History & Culture

Discovery and Synthesis

Diamorphine was first synthesized in 1874 by C.R. Alder Wright, an English chemist working at St. Mary's Hospital Medical School in London.²⁰ Wright had been experimenting with combining morphine with various acids, achieving the synthesis by boiling anhydrous…

Legality

International

1961 Convention: Schedule I.

1971 Convention: not internationally scheduled.

1988 Convention: not internationally scheduled.

By Country

United StatesIllegalSchedule I

Controlled Substances Act⁷²⁷³⁷⁴

Controlled under the Controlled Substances Act as an opium derivative.⁷⁵ Manufacturing, buying, possessing, or distributing without a DEA license is illegal. Heroin was federally prohibited in 1924 through the Heroin Act.

AustriaIllegalAnlage I

Suchtmittelgesetz³⁰

Illegal to possess, produce, and sell under the Suchtmittelgesetz (SMG), Austria's Narcotic Substances Act.³¹

CanadaPrescription onlySchedule I

Controlled Drugs and Substances Act³⁴

Controlled under the Controlled Drugs and Substances Act.³⁵ Since September 2016, Health Canada has permitted prescription of pharmaceutical diacetylmorphine to severe addicts as a treatment regimen.³⁶ A 2011 Supreme Court decision established a constitutional right under Section 7 of the Charter of Rights and Freedoms to access supervised injection sites.³⁷

Czech RepublicDecriminalizedSchedule 3

Government Regulation No. 463/2013³⁹⁴⁰

Personal possession of 1.5g or less has been decriminalized, with penalties comparable to a parking fine. Sales, production, and possession of larger quantities remain criminal offenses.

GermanyPrescription onlyAnlage III

Betäubungsmittelgesetz^43444546

Heroin (diamorphine) is listed in Anlage III to Germany's Betäubungsmittelgesetz only in preparations authorised for substitution treatment. Anlage III narcotics may be prescribed by physicians, dentists or veterinarians only where administration is medically justified; diamorphine is supplied only by the pharmaceutical entrepreneur to recognised facilities on presentation of the prescription. Unauthorised cultivation, manufacture, trade, import, export, supply, acquisition and possession of narcotics are criminal offences.

ItalyIllegalTabella I

DPR 309/1990⁴⁸⁴⁹

Listed in Tabella I of the 'Tabelle delle sostanze stupefacenti e psicotrope.' Possession, purchase, and sale are illegal.

LatviaIllegalList I

Regulations No. 847⁵¹

Classified as a Schedule I controlled substance under Latvian drug legislation. Possession, production, and distribution are prohibited.

NetherlandsIllegalList I

Opium Act⁵³

Heroin is listed in List I of the Opium Act. List I substances are hard drugs and the Act prohibits their unauthorised possession, production, sale, import and export.

NorwayIllegalList I

Narkotikaforskriften⁵⁵

Illegal to buy or possess without a special license. The government has established needle exchange facilities where addicts can obtain clean injection equipment, though the substance itself remains prohibited.

PortugalDecriminalizedTable I-A

Law No. 30/2000⁵⁷⁵⁸

Personal use decriminalized by Law 30/2000, effective July 2001.⁵⁹ Possession of less than 1g is not a criminal offense, though the substance may be seized and the individual referred to a dissuasion commission for potential treatment. Sale or possession above the personal threshold remains a criminal offense punishable by imprisonment.

SingaporeIllegalClass A

Misuse of Drugs Act 1973⁶¹⁶²

Heroin, listed as diamorphine, is a Class A controlled drug under the First Schedule to the Misuse of Drugs Act 1973. The Act prohibits unauthorized possession, manufacture, trafficking, import and export of controlled drugs.

SpainPrescription onlyLista IV

Instrumento de Ratificación del Convenio Único de 1961 sobre Estupefacientes⁶⁵

Heroin (diacetylmorphine) is listed in Lista IV of Spain’s ratified Single Convention on Narcotic Drugs; Lista IV substances are also included in Lista I and subject to its controls. The Convention has applied to Spain since 31 March 1966 and permits possession only with legal authorization; manufacture, trade, and distribution are subject to licensing, and supply to individuals requires a medical prescription.

UkraineIllegalTable I

Cabinet of Ministers Resolution No. 770 of 6 May 2000⁶⁹

Heroin (diacetylmorphine) is included in Ukraine's official list of narcotic drugs, psychotropic substances and precursors. Listed narcotics are subject to state control and unauthorised handling is criminally regulated.

AustraliaSchedule I (Narcotic Drugs Act)Citation needed

Listed in Schedule I of the Narcotic Drugs Act of 1967. Personal quantities under 1 gram have been decriminalized in the Australian Capital Territory as of 28 October 2023.²⁹

BrazilIllegalLista A1

Portaria SVS/MS 344/1998³²³³

Listed as a controlled substance under national drug legislation. Production, distribution, and possession are prohibited.

ColombiaIllegalEstupefaciente

Decreto 1019 de 1990³⁸

Heroin (diacetylmorphine) appears in Colombia's official controlled-substances list. It is regulated as an estupefaciente under the national narcotics-control framework.

FinlandIllegalSchedule I

Government Decree 543/2008⁴¹⁴²

Classified as a controlled substance under Finnish law. Production, distribution, and possession are illegal without a license.

IndiaIllegalNarcotic drug

Narcotic Drugs and Psychotropic Substances Act, 1985⁴⁷

The Narcotic Drugs and Psychotropic Substances Act treats diacetylmorphine (heroin) as a narcotic drug. The Act prohibits unauthorised production, possession, sale, purchase, transport, use and related dealings.

JapanIllegalSchedule I

Narcotics and Psychotropics Control Act⁵⁰

Diacetylmorphine, also called heroin, is listed in Schedule I of Japan's Narcotics and Psychotropics Control Act. The Act controls the import, export, manufacture and transfer of narcotics.

MexicoIllegalArticle 237

Ley General de Salud⁵²

Diacetylmorphine or heroin, including its salts and preparations, is expressly covered by Article 237 of the General Health Law. The provision prohibits the acts described in Article 235 for this substance in Mexico.

New ZealandIllegalClass A

Misuse of Drugs Act 1975⁵⁴

Controlled as a Class A substance under the Misuse of Drugs Act, the most restrictive classification carrying the most severe penalties.

PolandIllegalGroup I-N

Act on Counteracting Drug Addiction⁵⁶

Illegal to produce, sell, and possess under the 'wykaz środków odurzających i substancji psychotropowych' (list of narcotic drugs and psychotropic substances).

RussiaIllegalList I

Government Resolution No. 681⁶⁰

Classified as a Schedule I controlled substance under Russian narcotic drug legislation. Possession, production, and distribution are prohibited.

South AfricaIllegalSchedule 2

Drugs and Drug Trafficking Act 140 of 1992⁶³⁶⁴

Heroin is listed in Schedule 2 of the Drugs and Drug Trafficking Act as a dangerous dependence-producing substance. Unauthorised dealing in and possession of listed substances are offences under the Act.

SwitzerlandPrescription onlyVerzeichnis d

Betäubungsmittelverzeichnisverordnung⁶⁶⁶⁷

Specifically named under Verzeichnis D of the Betäubungsmittelgesetz. Generally illegal to possess, but legally available to registered addicts through state-sanctioned heroin-assisted treatment programs.⁶⁸

United KingdomPrescription onlyClass A

Misuse of Drugs Act 1971⁷⁰⁷¹

Controlled under the Misuse of Drugs Act.⁷⁰ Illegal to buy, sell, or possess without a license. However, under the name diamorphine, it remains a legal prescription medication indicated for severe pain associated with surgical procedures, myocardial infarction, pain in terminally ill patients, and relief of dyspnoea in acute pulmonary edema.⁵

References

Source Pages

Citations

Suggest an edit

Spotted a mistake, an outdated claim, or something missing from the Heroin article? Send the editors a private note. Feedback lands in a moderation queue and is never shown on the site.

Heroin

Diacetylmorphine

Diamorphine, H, Smack, Junk, Brown

Psychoactive Class

Opioid Depressant Sedative

Chemical Class

Morphinan (substituted)

Dosage & Duration

Dosage

Threshold5-5 mg

Light7.5-20 mg

Moderate20-35 mg

Strong35-50 mg

Heavy50+ mg

Duration

Onset10-60 seconds

Come Up10-60 seconds

Peak1-90 minutes

Offset1-3 hours

After Effects1.5-3 hours

Total3-7 hours

Subjective Effects

Effects vary widely by individual, dose, and context.

Physical

The physical effects of heroin can be broken down into several components which progressively intensify proportional to dosage.

Respiratory depression Itchiness Constipation Cough suppression Difficulty urinating Nausea Sedation Pupil constriction

Cognitive

The cognitive effects of heroin can be broken down into several components which progressively intensify proportional to dosage.

Anxiety suppression Compulsive redosing

Visual

Forked from Subjective Effect Documentation

by Josie KinsJuly 2015.

Reagent Testing

Loading reagent data

Expected colorimetric results are being prepared.

Pharmacology

Pharmacodynamics

Pharmacokinetics

Interactions

Dangerous

Highest risk

These combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.

AlcoholBenzodiazepinesCocaineDXMGHB/GBLKetamineMXEPregabalinTramadol

Unsafe

Avoid

There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.

Diphenhydramine

Caution

Use caution

AmphetaminesMAOIsMephedroneNitrous oxidePCP

TripSit

Tolerance

Full Tolerance

Baseline Reset

1-2 weeks

Half Tolerance

3-7 days

Cross Tolerance

Opioids (all other opioid receptor agonists will have reduced effect after heroin consumption)

Harm Potential

Addiction & Dependence

Psychological

Extremely High

Physical

High

Toxicity

Respiratory

Respiratory depression is the primary mechanism of overdose death; heavy doses suppress breathing proportionally to the amount consumed, potentially reducing breathing rate to 2-4 breaths per minute.

Central Nervous System

Auditory

Heroin is known to be ototoxic, causing hearing loss, tinnitus, and balance issues; effects may persist long after use.¹²

Gastrointestinal

Constipation is a common and persistent effect with regular use, representing one of the few direct long-term complications of unadulterated heroin.

Urinary

Urinary retention and difficulty urinating can occur with chronic and repeated use.

Cardiovascular

Decreased heart rate and hypotension occur during intoxication; heroin use has been associated with myocardial infarction.¹³

Renal

Decreased kidney function (nephropathy) has been reported in intravenous users.¹⁵

Pulmonary

History & Culture

Discovery and Synthesis

Legality

International

1961 Convention: Schedule I.

1971 Convention: not internationally scheduled.

1988 Convention: not internationally scheduled.

By Country

United StatesIllegalSchedule I

Controlled Substances Act⁷²⁷³⁷⁴

AustriaIllegalAnlage I

Suchtmittelgesetz³⁰

Illegal to possess, produce, and sell under the Suchtmittelgesetz (SMG), Austria's Narcotic Substances Act.³¹

CanadaPrescription onlySchedule I

Controlled Drugs and Substances Act³⁴

Czech RepublicDecriminalizedSchedule 3

Government Regulation No. 463/2013³⁹⁴⁰

Personal possession of 1.5g or less has been decriminalized, with penalties comparable to a parking fine. Sales, production, and possession of larger quantities remain criminal offenses.

GermanyPrescription onlyAnlage III

Betäubungsmittelgesetz^43444546

ItalyIllegalTabella I

DPR 309/1990⁴⁸⁴⁹

Listed in Tabella I of the 'Tabelle delle sostanze stupefacenti e psicotrope.' Possession, purchase, and sale are illegal.

LatviaIllegalList I

Regulations No. 847⁵¹

Classified as a Schedule I controlled substance under Latvian drug legislation. Possession, production, and distribution are prohibited.

NetherlandsIllegalList I

Opium Act⁵³

Heroin is listed in List I of the Opium Act. List I substances are hard drugs and the Act prohibits their unauthorised possession, production, sale, import and export.

NorwayIllegalList I

Narkotikaforskriften⁵⁵

PortugalDecriminalizedTable I-A

Law No. 30/2000⁵⁷⁵⁸

SingaporeIllegalClass A

Misuse of Drugs Act 1973⁶¹⁶²

SpainPrescription onlyLista IV

Instrumento de Ratificación del Convenio Único de 1961 sobre Estupefacientes⁶⁵

UkraineIllegalTable I

Cabinet of Ministers Resolution No. 770 of 6 May 2000⁶⁹

AustraliaSchedule I (Narcotic Drugs Act)Citation needed

Listed in Schedule I of the Narcotic Drugs Act of 1967. Personal quantities under 1 gram have been decriminalized in the Australian Capital Territory as of 28 October 2023.²⁹

BrazilIllegalLista A1

Portaria SVS/MS 344/1998³²³³

Listed as a controlled substance under national drug legislation. Production, distribution, and possession are prohibited.

ColombiaIllegalEstupefaciente

Decreto 1019 de 1990³⁸

Heroin (diacetylmorphine) appears in Colombia's official controlled-substances list. It is regulated as an estupefaciente under the national narcotics-control framework.

FinlandIllegalSchedule I

Government Decree 543/2008⁴¹⁴²

Classified as a controlled substance under Finnish law. Production, distribution, and possession are illegal without a license.

IndiaIllegalNarcotic drug

Narcotic Drugs and Psychotropic Substances Act, 1985⁴⁷

JapanIllegalSchedule I

Narcotics and Psychotropics Control Act⁵⁰

Diacetylmorphine, also called heroin, is listed in Schedule I of Japan's Narcotics and Psychotropics Control Act. The Act controls the import, export, manufacture and transfer of narcotics.

MexicoIllegalArticle 237

Ley General de Salud⁵²

New ZealandIllegalClass A

Misuse of Drugs Act 1975⁵⁴

Controlled as a Class A substance under the Misuse of Drugs Act, the most restrictive classification carrying the most severe penalties.

PolandIllegalGroup I-N

Act on Counteracting Drug Addiction⁵⁶

Illegal to produce, sell, and possess under the 'wykaz środków odurzających i substancji psychotropowych' (list of narcotic drugs and psychotropic substances).

RussiaIllegalList I

Government Resolution No. 681⁶⁰

Classified as a Schedule I controlled substance under Russian narcotic drug legislation. Possession, production, and distribution are prohibited.

South AfricaIllegalSchedule 2

Drugs and Drug Trafficking Act 140 of 1992⁶³⁶⁴

SwitzerlandPrescription onlyVerzeichnis d

Betäubungsmittelverzeichnisverordnung⁶⁶⁶⁷

United KingdomPrescription onlyClass A

Misuse of Drugs Act 1971⁷⁰⁷¹

References

Source Pages

Citations

Suggest an edit

Spotted a mistake, an outdated claim, or something missing from the Heroin article? Send the editors a private note. Feedback lands in a moderation queue and is never shown on the site.

Heroin

Contents

Dosage & Duration

Dosage

Duration

Subjective Effects

Physical

Cognitive

Visual

Reagent Testing

Pharmacology

Pharmacodynamics

Pharmacokinetics

Interactions

Dangerous

Unsafe

Caution

Tolerance

Harm Potential

Addiction & Dependence

Psychological

Physical

Toxicity

History & Culture

Discovery and Synthesis

Legality

International

By Country

References

Source Pages

Citations

Further Reading

Suggest an edit

Heroin

Contents

Dosage & Duration

Dosage

Duration

Subjective Effects

Physical

Cognitive

Visual

Reagent Testing

Pharmacology

Pharmacodynamics

Pharmacokinetics

Interactions

Dangerous

Unsafe

Caution

Tolerance

Harm Potential

Addiction & Dependence

Psychological

Physical

Toxicity

History & Culture

Discovery and Synthesis

Legality

International

By Country

References

Source Pages

Citations

Further Reading

Suggest an edit