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Accession NumberDB01511
TypeSmall Molecule
GroupsApproved, Illicit
DescriptionDelorazepam is a benzodiazepine which, like other drugs in its class, possesses anxiolytic, skeletal muscle relaxant, hypnotic and anticonvulsant properties. It may have adverse effects such as drowsiness, and cognitive impairments such as short term memory impairment. [4] Delorazepam is an active metabolite of the benzodiazepine known as cloxazolam. It is a long acting benzodiazepine which makes it superior in this sense to lorazepam which is short acting. Lorazepam is also a major active metabolite of delorazepam. In addition to be long acting, delorazepam is relatively potent, with 1 mg of delorazepam being the equivalent of 10 mg diazepam. [Wikipedia] It has been approved for marketing in Italy.
External IDs Not Available
Product Ingredients Not Available
Approved Prescription ProductsNot Available
Approved Generic Prescription ProductsNot Available
Approved Over the Counter ProductsNot Available
Unapproved/Other Products Not Available
International Brands
Dadumir Not Available
Delorazepam AlmusAlmus
Delorazepam AlterAlter
Delorazepam AurobindoAurobindo
Delorazepam DOCDOC Generici
Delorazepam EGEG
Delorazepam GermedGermed Pharma
Delorazepam HexalHexal
Delorazepam MylanMylan
Delorazepam PensaPensa Pharma
Delorazepam RanbaxyRanbaxy Italia
Delorazepam ratiopharmRatiopharm Italia
Delorazepam SandozSandoz
Delorazepam TevaTeva Italia,
Delorazepam WinthropSanofi Winthrop
Brand mixturesNot Available
CAS number2894-67-9
WeightAverage: 305.159
Monoisotopic: 304.017018366
Chemical FormulaC15H10Cl2N2O
IndicationMainly used as an anti-anxiety agent. Studies have found delorazepam to be more effective in the first 4 weeks of use than antidepressants; however, after 4 weeks, antidepressants showed superior anti-anxiety effects. [Wikipedia] Anti-anxiety effects also appear to be weaker in elderly patients. [1] Effectiveness has also been observed in the treatment of alcohol withdrawal. Delorazapam was reported to be a manageable drug in that it did not exhibit severe side effects and did not require further therapies to control symptoms of withdrawal. [3]
Structured Indications Not Available
PharmacodynamicsNot Available
Mechanism of actionNot Available
Related Articles
Absorption77-87% oral bioavailability, with a relatively slow absorption rate. [5] Reaches peak plasma levels within 1-2 hours of administration. Food may slow absorption, however other pharmacokinetic variables remain unchanged. After multiple doses delorazepam accumulates, however accumulation is slower in younger patients.[1]
Volume of distribution

140 L/kg apparent volume of distribution in 11 patients with normal renal function; 47 L/kg in 11 patients with renal failure and on regular hemodialysis. 5

In another study, apparent volume of distribution was 65 L/kg in 8 patients with liver disease and 118.4 L/kg in 12 healthy controls. 2

Protein binding>90% protein bound. [5]

Delorazepam is metabolized at a relatively slow pace by the liver. The major metabolite (15-34% of the parent drug) is lorazepam. Older patients metabolize delorazepam slower than younger patients. [1]

Route of eliminationRenally eliminated.
Half lifeVery long elimination half life of 80-115 hours, varying with age. Elimination is slower as age increases. [1] Liver disease also impacts elimination half life, with impairment resulting in half lives up to 395 hours. [2]

Still detectable 72 hours after dosing in healthy patients. Patients with liver disease experienced a reduction in clearance from 0.13 to 0.25 ng/mLh. 2

ToxicityOlder patients metabolize delorazepam slower than younger patients and thus suffer from more adverse effects. [1]
Affected organismsNot Available
PathwaysNot Available
Pharmacogenomic Effects/ADRs Not Available
Drug Interactions
DrugInteractionDrug group
Ambroxol acefyllinateThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Ambroxol acefyllinate.Experimental
AminophyllineThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Aminophylline.Approved
ClozapineThe risk or severity of adverse effects can be increased when Delorazepam is combined with Clozapine.Approved
DyphyllineThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Dyphylline.Approved
FosphenytoinThe serum concentration of Fosphenytoin can be increased when it is combined with Delorazepam.Approved
HyaluronidaseThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Hyaluronidase.Approved, Investigational
MefloquineThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Mefloquine.Approved
MethadoneDelorazepam may increase the central nervous system depressant (CNS depressant) activities of Methadone.Approved
MianserinThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Mianserin.Approved
OlanzapineThe risk or severity of adverse effects can be increased when Olanzapine is combined with Delorazepam.Approved, Investigational
OrlistatThe serum concentration of Delorazepam can be decreased when it is combined with Orlistat.Approved, Investigational
PhenytoinThe serum concentration of Phenytoin can be increased when it is combined with Delorazepam.Approved, Vet Approved
Sodium oxybateDelorazepam may increase the central nervous system depressant (CNS depressant) activities of Sodium oxybate.Approved
TeduglutideThe serum concentration of Delorazepam can be increased when it is combined with Teduglutide.Approved
TheophyllineThe therapeutic efficacy of Delorazepam can be decreased when used in combination with Theophylline.Approved
Food InteractionsNot Available
Synthesis ReferenceNot Available
General References
  1. Bareggi SR, Nielsen NP, Leva S, Pirola R, Zecca L, Lorini M: Age-related multiple-dose pharmacokinetics and anxiolytic effects of delorazepam (chlordesmethyldiazepam). Int J Clin Pharmacol Res. 1986;6(4):309-14. [PubMed:2875955 ]
  2. Bareggi SR, Pirola R, Potvin P, Devis G: Effects of liver disease on the pharmacokinetics of intravenous and oral chlordesmethyldiazepam. Eur J Clin Pharmacol. 1995;48(3-4):265-8. [PubMed:7589052 ]
  3. Cazzato G, Gioseffi M, Torre P, Coppola N: [Prevention and therapy of delirium tremens with tiapride and chlordesmethyldiazepam]. Riv Neurol. 1982 Nov-Dec;52(6):331-42. [PubMed:6130594 ]
  4. Scarone S, Strambi LF, Cazzullo CL: Effects of two dosages of chlordesmethyldiazepam on mnestic-information processes in normal subjects. Clin Ther. 1981;4(3):184-91. [PubMed:6796270 ]
  5. Sennesael J, Verbeelen D, Vanhaelst L, Pirola R, Bareggi SR: Pharmacokinetics of intravenous and oral chlordesmethyldiazepam in patients on regular haemodialysis. Eur J Clin Pharmacol. 1991;41(1):65-8. [PubMed:1782980 ]
External Links
ATC CodesNot Available
AHFS CodesNot Available
PDB EntriesNot Available
FDA labelNot Available
MSDSNot Available
Clinical Trials
Clinical Trials
Not AvailableCompletedTreatmentAnorexia Nervosa (AN) / Bulimia Nervosa (BN)1
ManufacturersNot Available
PackagersNot Available
Dosage formsNot Available
PricesNot Available
PatentsNot Available
Experimental Properties
logP3.15HANSCH,C & LEO,AJ (1985)
Predicted Properties
Water Solubility0.00642 mg/mLALOGPS
pKa (Strongest Acidic)12.29ChemAxon
pKa (Strongest Basic)2.05ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count2ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area41.46 Å2ChemAxon
Rotatable Bond Count1ChemAxon
Refractivity81.5 m3·mol-1ChemAxon
Polarizability29.44 Å3ChemAxon
Number of Rings3ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Predicted ADMET features
Human Intestinal Absorption+1.0
Blood Brain Barrier+0.9928
Caco-2 permeable+0.8835
P-glycoprotein substrateSubstrate0.5944
P-glycoprotein inhibitor INon-inhibitor0.7784
P-glycoprotein inhibitor IINon-inhibitor0.9457
Renal organic cation transporterNon-inhibitor0.5927
CYP450 2C9 substrateNon-substrate0.7891
CYP450 2D6 substrateNon-substrate0.9139
CYP450 3A4 substrateSubstrate0.7492
CYP450 1A2 substrateInhibitor0.9347
CYP450 2C9 inhibitorInhibitor0.5
CYP450 2D6 inhibitorNon-inhibitor0.7822
CYP450 2C19 inhibitorInhibitor0.7114
CYP450 3A4 inhibitorNon-inhibitor0.7519
CYP450 inhibitory promiscuityHigh CYP Inhibitory Promiscuity0.6921
Ames testNon AMES toxic0.9163
BiodegradationNot ready biodegradable1.0
Rat acute toxicity2.1516 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.9954
hERG inhibition (predictor II)Non-inhibitor0.8771
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397 )
Mass Spec (NIST)Not Available
Spectrum TypeDescriptionSplash Key
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, NegativeNot Available
MSMass Spectrum (Electron Ionization)splash10-0fb9-3594000000-3da2aad1da4843c38183View in MoNA
DescriptionThis compound belongs to the class of chemical entities known as 1,4-benzodiazepines. These are organic compounds containing a benzene ring fused to a 1,4-azepine.
KingdomChemical entities
Super ClassOrganic compounds
ClassOrganoheterocyclic compounds
Sub ClassBenzodiazepines
Direct Parent1,4-benzodiazepines
Alternative Parents
  • 1,4-benzodiazepine
  • Alpha-amino acid or derivatives
  • Chlorobenzene
  • Halobenzene
  • Aryl chloride
  • Aryl halide
  • Monocyclic benzene moiety
  • Benzenoid
  • Carboxamide group
  • Ketimine
  • Secondary carboxylic acid amide
  • Lactam
  • Carboxylic acid derivative
  • Azacycle
  • Organic 1,3-dipolar compound
  • Propargyl-type 1,3-dipolar organic compound
  • Organopnictogen compound
  • Imine
  • Organic oxygen compound
  • Organic nitrogen compound
  • Hydrocarbon derivative
  • Carbonyl group
  • Organic oxide
  • Organooxygen compound
  • Organohalogen compound
  • Organochloride
  • Organonitrogen compound
  • Aromatic heteropolycyclic compound
Molecular FrameworkAromatic heteropolycyclic compounds
External DescriptorsNot Available
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Drug created on July 31, 2007 07:10 / Updated on August 17, 2016 12:23