Delorazepam

Chlordesmethyldiazepam, Nordiclazepam, EN, Dadumir

Psychoactive Class

Depressant Anxiolytic GABAergic Muscle Relaxant

Chemical Class

Delorazepam is a benzodiazepine derivative of desmethyldiazepam, primarily used in the treatment of anxiety disorders¹ and alcohol withdrawal.² It is marketed in Italy and is notable for its exceptionally long half-life of 60 to 140 hours.³⁴ Delorazepam also serves as an active metabolite of both diclazepam⁵ and cloxazolam.⁶ Like other benzodiazepines, it possesses anxiolytic, muscle relaxant, hypnotic, and anticonvulsant properties,⁷⁸ and carries a risk of dependence with repeated use.⁹

Dosage & Duration

Dosage

Threshold~0.25 mg

Light0.25-0.5 mg

Moderate0.5-1.5 mg

Strong1.5-2 mg

Heavy2+ mg

Bioavailability

~77%

Delorazepam is approximately ten times more potent than diazepam on a milligram-per-milligram basis. The risk of memory impairment and amnestic blackouts increases significantly at higher doses.

Duration

Onset30-60 minutes

After Effects72 hours

Total12-16 hours

Half-life

80-115 hours

Subjective Effects

The experience is dominated by anxiety relief, sedation, and muscle relaxation, following the classic profile of a long-acting benzodiazepine with hypnotic and anticonvulsant properties. Disinhibition, increased talkativeness, and mild euphoria can accompany the calm, while memory formation becomes unreliable at higher doses. Due to its long duration of action, residual hangover-type drowsiness and impairment can persist well after the main effects subside.

Physical

The body feels heavy, relaxed, and sedated, with skeletal muscle relaxation, dizziness, and unsteady, uncoordinated movement. Respiratory depression becomes a concern at high doses or in combination with other depressants.

Impairment

Dizziness

Sedation

Cognitive

The headspace is calm and disinhibited, with suppressed anxiety, impaired judgement, and pronounced short-term memory impairment. Paradoxical reactions of increased anxiety, excitation, or aggression can occur, particularly in elderly, pediatric, and schizophrenic users, and depressive symptoms may emerge with continued use.

Emotional

Euphoria

Suppressions

Pharmacology

Pharmacodynamics

Delorazepam acts as a positive allosteric modulator at the GABA-A receptor, binding at the benzodiazepine site.¹⁰ This enhances the inhibitory signaling of GABA, producing the anxiolytic, sedative, and muscle relaxant properties characteristic of benzodiazepines.

Pharmacokinetics

Delorazepam is well absorbed after oral administration, reaching peak plasma levels within 1 to 2 hours, with a bioavailability of approximately 77%.³ It undergoes slow hepatic metabolism, producing lorazepam as an active metabolite that represents about 15 to 24 percent of the parent compound.³ The elimination half-life is reported as 80 to 115 hours,⁴ though one study found an average of 204 hours in healthy patients.¹¹ Significant accumulation occurs with repeated dosing due to this slow metabolism.¹² The elderly metabolize delorazepam and its active metabolite more slowly than younger individuals;¹² liver disease profoundly extends the half-life, with one report showing values reaching approximately 395 hours.¹¹ Delorazepam is itself an active metabolite of both diclazepam and cloxazolam.

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.

AlcoholGHB/GBLOpioidsTramadol

Unsafe

Avoid

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

DiphenhydraminePCP

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.

DXMKetamineMXE

TripSit

Tolerance

Full Tolerance

Tolerance to the sedative and anxiolytic effects develops with repeated use, as is characteristic of benzodiazepines. Due to the exceptionally long half-life of delorazepam, tolerance may develop more gradually compared to shorter-acting benzodiazepines, though accumulation with repeated dosing can complicate this pattern.

Cross Tolerance

Benzodiazepines, GABAergic depressants (barbiturates, alcohol, GHB/GBL), Z-drugs (zopiclone, zolpidem, zaleplon)

Harm Potential

Addiction & Dependence

Psychological

Moderate

Delorazepam is classified as habit-forming with recognized abuse potential.¹³ Patients with a history of substance or alcohol use are believed to have an increased risk of abuse.¹⁴ Non-medical use in prescribed patients has been documented and generally develops slowly, becoming evident only after months or years of therapy.

Physical

Extremely High

Physical dependence is the most serious effect of long-term use, with withdrawal symptoms that mimic delirium tremens.¹³ Although withdrawal effects are generally less severe than shorter-acting benzodiazepines, they can be life-threatening.¹³ Slow tapering over weeks or months is recommended to minimize withdrawal severity. Psychological effects such as rebound anxiety and insomnia may persist for months after physical dependence has been treated.¹³

Toxicity

Central Nervous System

Long-term use has been associated with cognitive deficits that may persist longer than six months, with some researchers suggesting these effects could be permanent;¹⁵ short-term use carries minimal risk of lasting cognitive impairment.

Psychosis Risk

Paradoxical reactions including increased anxiety, excitation, aggression, and hallucinations may occur but are uncommon. These reactions are more frequent in elderly, pediatric, and schizophrenic patients.¹⁶ In rare instances, delorazepam may cause suicidal ideation and actions.⁹ Contraindicated in patients with severe schizophrenia or schizo-affective disorders.

History & Culture

Delorazepam is an uncommon benzodiazepine that has been marketed primarily in Italy, where it is available under the trade name EN.⁹ The compound is notable for its relationship to other benzodiazepines in this class, serving as an active metabolite of both…

Legality

By Country

United StatesPrescription onlySchedule IV

Schedule IV, Controlled Substances Act⁵⁹

Delorazepam is listed in Schedule IV of the Controlled Substances Act. Its manufacture, distribution, and dispensing are federally controlled.

By state

All 50 U.S. states, the District of Columbia, and five territories were reviewed against the settled federal baseline. 35 jurisdictions had source-backed mirror treatment; 19 remain research gaps. 2 supported divergent jurisdiction findings survived independent review.

New MexicoIllegalSchedule I

PennsylvaniaIllegalSchedule I

BelgiumRestrictedAnnex III

Royal Decree of 6 September 2017 regulating narcotic drugs and psychotropic substances, Annex III¹⁸¹⁹²⁰

Belgium lists delorazepam in Annex III, which covers substances in Tables III and IV of the 1971 Convention’s Green List that are not in Annex II. The Royal Decree applies to products listed in its annexes and requires an activity authorisation for import, export, transport, manufacture, possession, sale, supply, dispensing, or acquisition. Legally obtained medicines are excepted from that authorisation requirement, but public dispensing requires a signed and dated medical prescription.

CanadaPrescription onlySchedule IV

Schedule IV, Controlled Drugs and Substances Act²³

Delorazepam is a Schedule IV substance under the Controlled Drugs and Substances Act. The Act subjects its handling to the federal controls applicable to that schedule.

ColombiaRestrictedLista Verde IV

Resolution No. 000116 of 2026, Technical Annex 1 (amending Resolution 315 of 2020)²⁵

Delorazepam is expressly listed in Technical Annex 1 as DELORAZEPAM, with the chemical name 7-cloro-5-(o-clorofenil)-1,3-dihidro-2H-1,4-benzodiazepin-2-ona, under Lista Verde, Lista IV. The resolution subjects Annex 1 substances and medicines or mixtures containing them to fiscalización; it takes effect on issuance and modifies the annexes to Resolution 315 of 2020.

FinlandIllegalNarcotic drug

Government Decree on substances, preparations and plants considered narcotics (543/2008), Annex II, Schedule IV²⁸²⁹

Delorazepam is listed as "Deloratsepaami" in Annex II, Schedule IV, the 1971 Psychotropic Convention list, of Government Decree 543/2008. Finland's Narcotics Act prohibits the production, manufacture, import, export, transport, distribution, trade, handling, possession and use of narcotics, subject to statutory medical, research and control exceptions.

IndiaRestrictedNDPS Act · Schedule item 42

Narcotic Drugs and Psychotropic Substances Act, 1985, Schedule item 42; sections 2(xxiii), 8(c), and 9(1)(a)(vi); Narcotic Drugs and Psychotropic Substances Rules, 1985, rules 53 and 55³¹³²

Delorazepam is a psychotropic substance under the Act Schedule. Section 8(c) prohibits listed operations except for medical or scientific purposes and in the manner and extent provided by the Act, rules, or orders; section 9 authorizes rules to permit and regulate psychotropic substances. It is not listed in the current NDPS Rules Schedule I, whose listed psychotropic substances are subject to the Schedule-I proviso in rule 53; imports of psychotropic substances otherwise require an import certificate under rule 55. This is therefore a restricted regulatory status, not a current NDPS Rules Schedule-I prohibition. The cited primary sources do not establish a general retail prescription-only classification for Delorazepam.

JapanRestrictedThird-Class Psychotropic

Narcotics and Psychotropics Control Act; Cabinet Order Specifying Narcotics, Narcotic Raw Material Plants, Psychotropic Substances and Narcotic/Psychotropic Raw Materials³⁴³⁵³⁶

Japan designates Delorazepam (デロラゼパム), including its salts, as a psychotropic substance under Article 4(15) of the Cabinet Order made under the Narcotics and Psychotropics Control Act. The Ministry of Health, Labour and Welfare's current psychotropic-substances list classifies it as a Third-Class Psychotropic, and the Narcotics Control Department treats prescribed psychotropics as subject to documented personal carriage rules when relevant thresholds are exceeded.

New ZealandIllegalClass C controlled drug

Misuse of Drugs Act 1975, Schedule 3, Part 5³⁹

Delorazepam is expressly listed in Part 5 of Schedule 3 to the Misuse of Drugs Act 1975. Part 5 is the Act's list of Class C controlled drugs, so Delorazepam is controlled under that Act.

PhilippinesPrescription onlySchedule IV

Republic Act No. 9165 (Comprehensive Dangerous Drugs Act of 2002); DDB Updated Lists of Scheduled Controlled Substances as of 06 July 2025⁴²⁴³⁴⁴

The Dangerous Drugs Board's current list, dated 06 July 2025, expressly places Delorazepam in Schedule IV. Republic Act No. 9165 defines the schedules annexed to the 1971 Convention as dangerous drugs and itself lists DELORAZEPAM in Schedule IV. DDB Board Regulation No. 1, s. 2014 provides that FDA-registered oral preparations in Philippine Schedule 4 require an ordinary prescription in triplicate.

PortugalPrescription onlyTabela IV

Decreto-Lei n.º 15/93, de 22 de janeiro⁴⁷

Delorazepam is listed in Tabela IV as 7-cloro-5-(2-clorofenil)-1,3-di-hidro-2H-1,4-benzodiazepina-2-ona. Substances and preparations in Tabela IV are subject to medical prescription under the general law, while the decree-law subjects their manufacture, distribution, importation, possession and use to its controls.

SpainPrescription onlyLista IV psicotrópicos

Real Decreto 2829/1977, de 6 de octubre⁵⁰

Delorazepam is expressly listed as a List IV psychotropic in Annex 1 to Real Decreto 2829/1977. The Decree requires a medical prescription for preparations containing List IV substances and prior authorization for their import or export.

UkrainePrescription onlyTable III · List 2

Cabinet of Ministers Resolution No. 770 of 6 May 2000, Table III, List No. 2; Law of Ukraine No. 60/95-VR, Article 27⁵⁴⁵⁵⁵⁶

Resolution No. 770 directly lists Delorazepam in Table III, List No. 2, whose heading describes psychotropic substances with restricted circulation for which exceptions to some control measures are permitted. Article 27 requires an electronic physician prescription for an individual’s medically indicated acquisition of medicines containing Table III psychotropic substances. This status concerns an authorised medicine containing Delorazepam, not unsupervised possession or supply of the raw substance. The current consolidated Resolution No. 770 incorporates Resolution No. 146 of 5 February 2026, effective 7 February 2026; Resolution No. 146 amended Tables I, II, and IV and did not amend the Table III Delorazepam entry.

AustraliaRestrictedSchedule 4 drug

Customs (Prohibited Imports) Regulations 1956, Schedule 4 (Drugs)¹⁷

Delorazepam is expressly listed as item 50 of Schedule 4 (Drugs) to the Customs (Prohibited Imports) Regulations 1956. Regulation 5 prohibits its importation into Australia unless the importer holds both a drug-import licence and a permission to import the drug. This entry records the verified federal import restriction and does not determine additional state or territory possession or supply rules.

BrazilPrescription onlyLista B1

RDC Anvisa nº 1.036, de 9 de julho de 2026 (Atualização nº 101 do Anexo I da Portaria SVS/MS nº 344/1998)²¹²²

Anvisa's current Atualização nº 101 expressly lists Delorazepam as item 30 of Lista B1. Lista B1 is the list of psychotropic substances subject to Notificação de Receita B, so Delorazepam is subject to that controlled prescription notification.

ChilePrescription onlyLista IV

Decreto Supremo N.º 405/1983, Reglamento de Productos Psicotrópicos, Lista IV²⁴

Chile lists delorazepam by name in Lista IV of the Reglamento de Productos Psicotrópicos. Products in Lista IV are dispensed with a receta médica retenida.

DenmarkPrescription onlyList E controlled

Bekendtgørelse nr. 405 af 26. marts 2026 om euforiserende stoffer²⁶²⁷

Delorazepam is expressly listed as Delorazepam INN, E022, on List E of Denmark’s controlled euphoriant-substances schedule. List E substances may only be used for medical and scientific purposes, and the Danish Medicines Agency states that private individuals may receive or possess a covered substance only when it has been prescribed by a doctor.

FranceRestrictedPsychotrope

Arrêté du 22 février 1990 fixant la liste des substances psychotropes³⁰

Delorazepam is listed in the first part of the annex to the Arrêté du 22 février 1990 as a psychotropic substance. Article 1 classifies the annexed products as psychotropic substances and extends the classification to their salts; the first part also includes preparations containing them or their salts.

IrelandRestrictedControlled drug

Misuse of Drugs Act, 1977 (Controlled Drugs) (Declaration) Order, 1987³³

Delorazepam is declared a controlled drug for the purposes of the Misuse of Drugs Act 1977. The declaration also covers salts, stereoisomeric forms, and preparations specified by the Order.

NetherlandsIllegalLijst II

Opiumwet³⁷³⁸

Delorazepam is expressly listed on Lijst II of the Netherlands’ Opiumwet. Article 3 prohibits importing or exporting, supplying, possessing, and manufacturing List II substances, subject to the Act’s stated exceptions.

NorwayRestrictedP IV

Forskrift om narkotika (narkotikaforskriften), FOR-2013-02-14-199 (Narkotikalisten)⁴⁰⁴¹

The current Narkotikalisten entry lists Delorazepam as P IV. Under § 3 of the regulation, substances listed in Narkotikalisten are narcotics; this entry is not marked as prohibited under § 5.

PolandPrescription onlyIV-P psychotropic

Rozporządzenie Ministra Zdrowia z dnia 17 sierpnia 2018 r. w sprawie wykazu substancji psychotropowych, środków odurzających oraz nowych substancji psychoaktywnych⁴⁵⁴⁶

Delorazepam is listed at item 16 of Poland's Group IV-P psychotropic-substance schedule. Group IV-P psychotropics may be used only for medical, industrial, or research purposes, and preparations containing them may be dispensed by pharmacies on prescription.

SingaporeRestrictedPsychotropic substance

Health Products (Therapeutic Products) Regulations 2016, First Schedule⁴⁸⁴⁹

Delorazepam is named in the First Schedule to the Health Products (Therapeutic Products) Regulations 2016, which is titled "Psychotropic substances". The Regulations define a psychotropic substance as one specified in that Schedule, and the Health Sciences Authority requires approval to import or export products containing psychotropic substances.

ThailandPrescription onlyCategory IV psychotropic

Table of Controlled Psychotropic Substances under Narcotics Code (PSYCHO list, update 25.07.2025)⁵¹⁵²⁵³

Thailand's FDA lists Delorazepam by that exact name in its current Table of Controlled Psychotropic Substances under the Narcotics Code as a Category IV psychotropic substance. Category 4 substances have medical use and a lower likelihood or potential for abuse than Category 3 substances. For personal travel, medication containing a Category IV psychotropic substance must be accompanied by a physician's certificate or prescription; the FDA's traveler guidance permits up to a 30-day prescribed supply without a permit and requires an FDA permit for a prescribed 31- to 90-day supply.

United KingdomRestrictedClass C · Schedule 4 Part I

Misuse of Drugs Act 1971, Schedule 2 Part III; Misuse of Drugs Regulations 2001, Schedule 4 Part I⁵⁷⁵⁸

The current official texts expressly name Delorazepam as a Class C drug and as a Schedule 4 Part I controlled drug. The available canonical vocabulary has no controlled-drug value, so restricted_other represents this controlled-drug restriction; no prescription-only-medicine classification is asserted because the inspected controlled-drug instruments do not establish one.

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Delorazepam

Chlordesmethyldiazepam, Nordiclazepam, EN, Dadumir

Psychoactive Class

Depressant Anxiolytic GABAergic Muscle Relaxant

Chemical Class

Benzodiazepine