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2D Structure
Also known as: Restoril, Hydroxydiazepam, Methyloxazepam, Levanxol, Oxydiazepam, Levanxene
Molecular Formula
C16H13ClN2O2
Molecular Weight
300.74  g/mol
InChI Key
SEQDDYPDSLOBDC-UHFFFAOYSA-N
FDA UNII
CHB1QD2QSS

A benzodiazepine that acts as a GAMMA-AMINOBUTYRIC ACID modulator and anti-anxiety agent.
Temazepam is a Benzodiazepine.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
7-chloro-3-hydroxy-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one
2.1.2 InChI
InChI=1S/C16H13ClN2O2/c1-19-13-8-7-11(17)9-12(13)14(18-15(20)16(19)21)10-5-3-2-4-6-10/h2-9,15,20H,1H3
2.1.3 InChI Key
SEQDDYPDSLOBDC-UHFFFAOYSA-N
2.1.4 Canonical SMILES
CN1C2=C(C=C(C=C2)Cl)C(=NC(C1=O)O)C3=CC=CC=C3
2.2 Other Identifiers
2.2.1 UNII
CHB1QD2QSS
2.3 Synonyms
2.3.1 MeSH Synonyms

1. 3 Hydroxydiazepam

2. 3-hydroxydiazepam

3. Apo Temazepam

4. Apo-temazepam

5. Dasuen

6. Euhypnos

7. Gen Temazepam

8. Gen-temazepam

9. Hydroxydiazepam

10. Levanxol

11. Methyloxazepam

12. Nocturne

13. Norkotral Tema

14. Normison

15. Normitab

16. Nortem

17. Novo Temazepam

18. Novo-temazepam

19. Nu Temazepam

20. Nu-temazepam

21. Oxydiazepam

22. Planum

23. Pms Temazepam

24. Pms-temazepam

25. Pronervon T

26. Remestan

27. Restoril

28. Ro 5 5345

29. Ro-5-5345

30. Ro55345

31. Sah 47 603

32. Sah 47-603

33. Sah 47603

34. Signopam

35. Tema, Norkotral

36. Temaze

37. Temazep Von Ct

38. Temtabs

39. Tenox

40. Von Ct, Temazep

41. Wy 3917

42. Wy-3917

43. Wy3917

2.3.2 Depositor-Supplied Synonyms

1. Restoril

2. Hydroxydiazepam

3. Methyloxazepam

4. Levanxol

5. Oxydiazepam

6. Levanxene

7. Crisonar

8. Euhypnos

9. Signopam

10. 846-50-4

11. N-methyloxazepam

12. Mabertin

13. Normison

14. Remestan

15. Planum

16. 3-hydroxydiazepam

17. Cerepax

18. Euipnos

19. Temaz

20. Tenox

21. Wy-3917

22. Temazepamum

23. Er 115

24. (rs)-temazepam

25. Ro 5-5345

26. Wy 3917

27. Temazepam, Pharmaceutical Grade

28. K-3917

29. Temazepam Civ

30. 2h-1,4-benzodiazepin-2-one, 7-chloro-1,3-dihydro-3-hydroxy-1-methyl-5-phenyl-

31. Nsc 246303

32. 7-chloro-3-hydroxy-1-methyl-5-phenyl-3h-1,4-benzodiazepin-2-one

33. Chb1qd2qss

34. Nocturne

35. Normitab

36. Temtabs

37. Dasuen

38. Nortem

39. Norkotral Tema

40. Nsc-246303

41. Temazep Von Ct

42. Pronervon T

43. 1,3-dihydro-7-chloro-3-hydroxy-1-methyl-5-phenyl-2h-1,4-benzodiazepin-2-one

44. Chebi:9435

45. Nomapam

46. Temador

47. Lenal

48. Uvamin Retard

49. Neodorm Sp

50. 7-chloro-3-hydroxy-1-methyl-5-phenyl-1,3-dihydro-2h-1,4-benzodiazepin-2-one

51. Ncgc00159440-02

52. Gelthix

53. Levanzene

54. Perdorm

55. Dsstox_cid_1309

56. Dsstox_rid_76071

57. Dsstox_gsid_21309

58. Temazepamum [inn-latin]

59. Strazepam

60. 7-chloro-3-hydroxy-1-methyl-5-phenyl-2,3-dihydro-1h-1,4-benzodiazepin-2-one

61. Restoril (tn)

62. Cas-846-50-4

63. Ccris 1954

64. Temazepam (usp/inn)

65. K3917

66. Unii-chb1qd2qss

67. Einecs 212-688-1

68. Brn 0759300

69. Dea No. 2925

70. Temazepam [usan:usp:inn:ban]

71. Diazepam, 3-hydroxy

72. (+/-)-temazepam

73. Wy 2917

74. Temazepam [inn]

75. Temazepam [mi]

76. Temazepam [iarc]

77. Temazepam [usan]

78. Temazepam [vandf]

79. Chembl967

80. Temazepam [mart.]

81. Temazepam [who-dd]

82. Schembl29463

83. 5-25-02-00242 (beilstein Handbook Reference)

84. Mls003899242

85. Divk1c_000989

86. Temazepam, Analytical Standard

87. Gtpl7300

88. Temazepam [orange Book]

89. Temazepam Civ [usp-rs]

90. Dtxsid8021309

91. Temazepam [ep Monograph]

92. Hms503e19

93. Kbio1_000989

94. Temazepam [usp Monograph]

95. Ninds_000989

96. Temazepam 1.0 Mg/ml In Methanol

97. Tox21_111670

98. Tox21_200044

99. Bdbm50408032

100. Nsc246303

101. Ccg-213642

102. Db00231

103. Ro-5-5354

104. Idi1_000989

105. Ncgc00159440-03

106. Ncgc00257598-01

107. Smr000238146

108. Wln: T67 Gnv Jn Ihj Cg G1 Iq Kr

109. C07125

110. D00370

111. Ab01563160_01

112. Q414796

113. Temazepam, British Pharmacopoeia (bp) Reference Standard

114. 2h-1, 7-chloro-1,3-dihydro-3-hydroxy-1-methyl-5-phenyl-

115. Temazepam, United States Pharmacopeia (usp) Reference Standard

116. Temazepam; T8275_sigma; Divk1c_000989; Ninds_000989

117. 1-methyl-7-chloro-3-hydroxy-5-phenyl-1,3-dihydro-2h-1,4-benzodiazepine-2-one

118. 2h-1,4-benzodiazepin-2-one, 1,3-dihydro-7-chloro-3-hydroxy-1-methyl-5-phenyl-

119. 3-hydroxy-1,3-dihydro-1-methyl-7-chloro-5-phenyl-2h-1,4-benzodiazepin-2-one

120. 7-chloro-3-hydroxy-1-methyl-5-phenyl-1,3-dihydro-2h-1,4-benzodiazepin-2-one #

121. 7-chloro-3-hydroxy-1-methyl-5-phenyl-1,3-dihydro-2h-benzo[e][1,4]diazepin-2-one

122. Temazepam Solution, 1.0 Mg/ml In Methanol, Ampule Of 1 Ml, Certified Reference Material

2.4 Create Date
2005-03-25
3 Chemical and Physical Properties
Molecular Weight 300.74 g/mol
Molecular Formula C16H13ClN2O2
XLogP32.2
Hydrogen Bond Donor Count1
Hydrogen Bond Acceptor Count3
Rotatable Bond Count1
Exact Mass300.0665554 g/mol
Monoisotopic Mass300.0665554 g/mol
Topological Polar Surface Area52.9 Ų
Heavy Atom Count21
Formal Charge0
Complexity434
Isotope Atom Count0
Defined Atom Stereocenter Count0
Undefined Atom Stereocenter Count1
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Drug Information
1 of 4  
Drug NameRestoril
PubMed HealthTemazepam (By mouth)
Drug ClassesAntianxiety, Hypnotic
Drug LabelRestoril (temazepam) is a benzodiazepine hypnotic agent. The chemical name is 7-chloro-1,3-dihydro-3-hydroxy-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one, and the structural formula is: Temazepam is a white, crystalline substance, very slightly so...
Active IngredientTemazepam
Dosage FormCapsule
RouteOral
Strength22.5mg; 7.5mg; 30mg; 15mg
Market StatusPrescription
CompanyMallinckrodt

2 of 4  
Drug NameTemazepam
PubMed HealthTemazepam (By mouth)
Drug ClassesAntianxiety, Hypnotic
Drug LabelDESCRIPTIONTemazepam is a benzodiazepine hypnotic agent. The chemical name is 7-chloro1,3-dihydro-3-hydroxy-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one, and the structural formula is:C16H13ClN2O2...
Active IngredientTemazepam
Dosage FormCapsule
RouteOral
Strength22.5mg; 7.5mg; 30mg; 15mg
Market StatusPrescription
CompanySandoz; Novel Labs; Actavis Elizabeth; Mutual Pharm; Mylan

3 of 4  
Drug NameRestoril
PubMed HealthTemazepam (By mouth)
Drug ClassesAntianxiety, Hypnotic
Drug LabelRestoril (temazepam) is a benzodiazepine hypnotic agent. The chemical name is 7-chloro-1,3-dihydro-3-hydroxy-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one, and the structural formula is: Temazepam is a white, crystalline substance, very slightly so...
Active IngredientTemazepam
Dosage FormCapsule
RouteOral
Strength22.5mg; 7.5mg; 30mg; 15mg
Market StatusPrescription
CompanyMallinckrodt

4 of 4  
Drug NameTemazepam
PubMed HealthTemazepam (By mouth)
Drug ClassesAntianxiety, Hypnotic
Drug LabelDESCRIPTIONTemazepam is a benzodiazepine hypnotic agent. The chemical name is 7-chloro1,3-dihydro-3-hydroxy-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one, and the structural formula is:C16H13ClN2O2...
Active IngredientTemazepam
Dosage FormCapsule
RouteOral
Strength22.5mg; 7.5mg; 30mg; 15mg
Market StatusPrescription
CompanySandoz; Novel Labs; Actavis Elizabeth; Mutual Pharm; Mylan

4.2 Drug Indication

Temazepam is specifically indicated only for the short-term management of insomnia,. Furthermore, such management is generally predominantly associated with the symptomatic relief of transient and short-term insomnia characterized by difficulty in falling asleep, frequent nocturnal awakenings and/or early morning awakenings. In particular, the official prescribing information for temazepam typically specifies that the instructions issued for dispensed prescriptions of the medication should indicate specifically that patients are only expected to use the therapy for short periods of time - usually 7-10 days in general. Subsequently, treatment with temazepam should usually not exceed 7 to 10 consecutive days and nor should it be prescribed in quantities exceeding a one-month supply. Some regional prescribing information also notes that temazepam may be used for premedication prior to minor surgery or other related procedures.


FDA Label


5 Pharmacology and Biochemistry
5.1 Pharmacology

Temazepam is a benzodiazepine used as a hypnotic agent in the management of insomnia. Temazepam produces CNS depression at limbic, thalamic, and hypothalamic levels of the CNS. Temazepam increases the affinity of the neurotransmitter gamma-aminobutyric acid (GABA) for GABA receptors by binding to benzodiazepine receptors. Results are sedation, hypnosis, skeletal muscle relaxation, anticonvulsant activity, and anxiolytic action. In sleep laboratory studies, the effect of temazepam was compared to placebo during a two week period. The studies demonstrated a linear dose-response improvement in total sleep time and sleep latency with substantial drug-placebo differences apparent for total sleep time and for sleep latency at higher doses of temazepam. Regardless, REM sleep was ultimately unchanged but slow wave sleep was decreased. Moreover, a transient syndrome, known as "rebound insomnia", wherein the symptoms that led to treatment with temazepam in the first place recur in an enhanced form, may happen on withdrawal of temazepam treatment. The possibility of this occurrence is in part why long term use of temazepam is not recommended due to worries over tolerance and dependence wherein patients' bodies become physiologically accustomed to the regular presence and pharmacological effect of higher and higher doses of the benzodiazepine used. The duration of hypnotic effect and the profile of unwanted adverse effects may be influenced by the distribution and elimination half-lives of the administered temazepam and any active metabolites that may be formed. When such half-lives are long, the drug or its metabolite(s) may accumulate during periods of nightly administration and be associated with impairments of cognitive and motor performance during waking hours. Conversely, if half-lives are short, the drug and metabolites would be cleared before the next dose is ingested, and carry-over effects related to sedation or CNS depression should be minimal or not present at all. However, during nightly use and for an extended period, pharmacodynamic tolerance or adaptation to some effects of benzodiazepine hypnotics may develop - which may also contribute to the possibility of 'rebound insomnia'. Consequently, if the drug has a very short elimination half-life, it is possible that a relative deficiency (for example, in relation to benzodiazepine GABA(a) receptor sites) may occur at some point in the interval between each night's use. This sequence of events may account for certain clinical findings reported happening after several weeks of nightly use of rapidly eliminated benzodiazepine hypnotics, including increased wakefulness during the last third of the night and the appearance of increased daytime anxiety.


5.2 MeSH Pharmacological Classification

GABA Modulators

Substances that do not act as agonists or antagonists but do affect the GAMMA-AMINOBUTYRIC ACID receptor-ionophore complex. GABA-A receptors (RECEPTORS, GABA-A) appear to have at least three allosteric sites at which modulators act: a site at which BENZODIAZEPINES act by increasing the opening frequency of GAMMA-AMINOBUTYRIC ACID-activated chloride channels; a site at which BARBITURATES act to prolong the duration of channel opening; and a site at which some steroids may act. GENERAL ANESTHETICS probably act at least partly by potentiating GABAergic responses, but they are not included here. (See all compounds classified as GABA Modulators.)


Anti-Anxiety Agents

Agents that alleviate ANXIETY, tension, and ANXIETY DISORDERS, promote sedation, and have a calming effect without affecting clarity of consciousness or neurologic conditions. ADRENERGIC BETA-ANTAGONISTS are commonly used in the symptomatic treatment of anxiety but are not included here. (See all compounds classified as Anti-Anxiety Agents.)


Hypnotics and Sedatives

Drugs used to induce drowsiness or sleep or to reduce psychological excitement or anxiety. (See all compounds classified as Hypnotics and Sedatives.)


5.3 FDA Pharmacological Classification
5.3.1 Active Moiety
TEMAZEPAM
5.3.2 FDA UNII
CHB1QD2QSS
5.3.3 Pharmacological Classes
Benzodiazepines [CS]; Benzodiazepine [EPC]
5.4 ATC Code

N - Nervous system

N05 - Psycholeptics

N05C - Hypnotics and sedatives

N05CD - Benzodiazepine derivatives

N05CD07 - Temazepam


5.5 Absorption, Distribution and Excretion

Absorption

Studies demonstrate that between 90 to 100% of an orally administered temazepam dose is absorbed, making the medication very well absorbed. The oral administration of 15 to 45 mg temazepam resulted in rapid absorption with significant blood levels achieved in 30 minutes and peak levels at 2-3 hours. In particular, direct studies following the oral ingestion of 30 mg of temazepam revealed measurable plasma concentrations were obtained 10-20 minutes after dosing with peak plasma levels ranging between 666-982 ng/mL (with a mean of 865 ng/mL) presenting approximately 1.2-1.6 hours (with a mean of 1.5 hours) after the dosing. Finally, a dose-proportional relationship was established for the area under the plasma concentration/time curve over the 15 to 30 mg dose range.


Route of Elimination

Following a single dose, 80-90% of the dose appears in the urine, predominantly as the O-conjugate metabolite, and 3-13% of the dose appears in the faeces. Less than 2% of the dose is excreted unchanged or as N-desmethyltemazepam in the urine.


Volume of Distribution

The volume of distribution documented for temazepam is 1.3-1.5 L/kg body weight - and in particular, 43-68 L/kg for the unbound fraction.


Clearance

Studies regarding the clearance of temazepam have recorded the values of 1.03 ml/min/kg and 31 ml/min/kg for the clearance of total temazepam and the clearance of unbound temazepam, respectively.


5.6 Metabolism/Metabolites

First-pass metabolism of temazepam is minimal at approximately 5-8% of an administered dose. Nevertheless, temazepam is principally metabolized in the liver where most of the unchanged drug is directly conjugated to glucuronide and excreted in the urine. In particular, the primary metabolite present in the blood is the O-conjugate of temazepam. Less than 5% of the drug is demethylated to oxazepam and subsequently eliminated as the glucuronide. Regardless, the glucuronides of temazepam have no demonstrable CNS activity and it is believed that no active metabolites are formed in general. Since temazepam mainly undergoes Phase II conjugation reactions, it is proposed that it is devoid of CYP450 interactions.


Temazepam is a known human metabolite of diazepam.

S73 | METXBIODB | Metabolite Reaction Database from BioTransformer | DOI:10.5281/zenodo.4056560


5.7 Biological Half-Life

The terminal half-life determined for temazepam is recorded as being between 3.5-18 hours, with a mean of 9 hours.


5.8 Mechanism of Action

Gamma-Aminobutyric acid (GABA) is considered the principal inhibitory neurotransmitter in the human body. When GABA binds to GABA(a) receptors found in neuron synapses, chloride ions are conducted across neuron cell membranes via an ion channel in the receptors. With enough chloride ions conducted, the local, associated neuron membrane potentials are hyperpolarized - making it more difficult or less likely for action potentials to fire, ultimately resulting in less excitation of the neurons. Subsequently, benzodiazepines like temazepam can bind to benzodiazepine receptors that are components of various varieties of GABA(a) receptors. This binding acts to enhance the effects of GABA by increasing GABA affinity for the GABA(a) receptor, which ultimately enhances GABA ligand binding at the receptors. This enhanced ligand binding of the inhibitory neurotransmitter GABA to the receptors increases the aforementioned chloride ion conduction (perhaps reportedly via an increase in the frequency of the chloride channel opening), resulting in a hyperpolarized cell membrane that prevents further excitation of the associated neuron cells. Combined with the notion that such benzodiazepine receptor associated GABA(a) receptors exist both peripherally and in the CNS, this activity consequently facilitates various effects like sedation, hypnosis, skeletal muscle relaxation, anticonvulsant activity, and anxiolytic action.