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2D Structure
Also known as: Xanax, 28981-97-7, Trankimazin, Niravam, Tafil, Tranquinal
Molecular Formula
C17H13ClN4
Molecular Weight
308.8  g/mol
InChI Key
VREFGVBLTWBCJP-UHFFFAOYSA-N
FDA UNII
YU55MQ3IZY

A triazolobenzodiazepine compound with antianxiety and sedative-hypnotic actions, that is efficacious in the treatment of PANIC DISORDERS, with or without AGORAPHOBIA, and in generalized ANXIETY DISORDERS. (From AMA Drug Evaluations Annual, 1994, p238)
Alprazolam is a Benzodiazepine.
1 2D Structure

2D Structure

2 Identification
2.1 Computed Descriptors
2.1.1 IUPAC Name
8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine
2.1.2 InChI
InChI=1S/C17H13ClN4/c1-11-20-21-16-10-19-17(12-5-3-2-4-6-12)14-9-13(18)7-8-15(14)22(11)16/h2-9H,10H2,1H3
2.1.3 InChI Key
VREFGVBLTWBCJP-UHFFFAOYSA-N
2.1.4 Canonical SMILES
CC1=NN=C2N1C3=C(C=C(C=C3)Cl)C(=NC2)C4=CC=CC=C4
2.2 Other Identifiers
2.2.1 UNII
YU55MQ3IZY
2.3 Synonyms
2.3.1 MeSH Synonyms

1. Alprazolan

2. Alprox

3. Apo Alpraz

4. Apo-alpraz

5. Cassadan

6. D-65mt

7. D65mt

8. Esparon

9. Kalma

10. Novo Alprazol

11. Novo-alprazol

12. Nu Alpraz

13. Nu-alpraz

14. Ralozam

15. Tafil

16. Trankimazin

17. U-31,889

18. U31,889

19. Xanax

2.3.2 Depositor-Supplied Synonyms

1. Xanax

2. 28981-97-7

3. Trankimazin

4. Niravam

5. Tafil

6. Tranquinal

7. Alplax

8. Constan

9. Frontal

10. Solanax

11. Xanor

12. Apo-alpraz

13. 8-chloro-1-methyl-6-phenyl-4h-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine

14. Xanax Xr

15. Alcelam

16. Anpress

17. Relaxol

18. Tricalma

19. Valeans

20. Xanagis

21. Zolarem

22. Alpaz

23. Alpram

24. Alzam

25. Panix

26. Prinox

27. Zoldac

28. Zotran

29. Alprazolam Intensol

30. Tus-1

31. Xanolam

32. Zolam

33. Zopax

34. Zopic

35. Tafil D

36. Xanax Ts

37. D 65mt

38. Alprazolam Civ

39. 8-chloro-1-methyl-6-phenyl-4h-s-triazolo(4,3-a)(1,4)benzodiazepine

40. U-31,889

41. Cassadan

42. Esparon

43. Neurol

44. U 31889

45. U-31889

46. Alpronax

47. Alzolam

48. Bestrol

49. Ralozam

50. Alprox

51. Restyl

52. Yu55mq3izy

53. Chembl661

54. Nsc-760140

55. Novo-alprazol

56. 8-chloro-1-methyl-6-phenyl-4h-s-triazolo[4,3-a][1,4]benzodiazepine

57. Nu-alpraz

58. Chebi:2611

59. Alprazolamum

60. Pharnax

61. Prazolan

62. Tensivan

63. Zacetin

64. Zanapam

65. Alprax

66. Ksalol

67. Mialin

68. Prazam

69. Unilan

70. Zoldax

71. Algad

72. Alzon

73. Helex

74. Zaxan

75. Zenax

76. Gen-alprazolan

77. 4h-s-triazolo(4,3-a)(1,4)benzodiazepine, 8-chloro-1-methyl-6-phenyl-

78. 4h-(1,2,4)triazolo(4,3-a)(1,4)benzodiazepine, 8-chloro-1-methyl-6-phenyl-

79. 4h-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine, 8-chloro-1-methyl-6-phenyl-

80. Ncgc00159466-02

81. Alprazolamum [inn-latin]

82. U 31,889

83. Tus 1

84. Panistat

85. Alprazolam Extended Release Tablets

86. Staccato-alprazolam

87. Smr000149316

88. Xanax (tn)

89. Hsdb 7207

90. Einecs 249-349-2

91. Unii-yu55mq3izy

92. Az-002

93. Tgar01p

94. Brn 1223125

95. Dea No. 2882

96. 08h

97. Alprazolam [usan:usp:inn:ban:jan]

98. Ap-1002

99. 3u5j

100. Alprazolam [mi]

101. Alprazolam [inn]

102. Alprazolam [jan]

103. Alprazolam [hsdb]

104. Alprazolam [usan]

105. Dsstox_cid_2577

106. Alprazolam [vandf]

107. Alprazolam [mart.]

108. Schembl8398

109. Alprazolam [who-dd]

110. Dsstox_rid_76639

111. Bidd:pxr0150

112. Dsstox_gsid_22577

113. Zinc903

114. Mls000559000

115. Mls000759485

116. Mls001423979

117. Bidd:gt0475

118. Alprazolam (jp17/usp/inn)

119. Gtpl7111

120. Alprazolam [ep Impurity]

121. Alprazolam [orange Book]

122. Dtxsid4022577

123. Alprazolam [ep Monograph]

124. Alprazolam [usp Monograph]

125. Hms2051a10

126. Hms3393a10

127. Pharmakon1600-01502395

128. Alprazolam 0.1 Mg/ml In Methanol

129. Alprazolam 1.0 Mg/ml In Methanol

130. Bcp28608

131. Tox21_111692

132. Bbl028160

133. Bdbm50001728

134. Nsc760140

135. Stk590494

136. Akos005066050

137. Ccg-100855

138. Db00404

139. Nc00105

140. Nsc 760140

141. 4h-(1,2,4)triazolo(4,3-alpha)(1,4)benzodiazepine, 8-chloro-1-methyl-6-phenyl-

142. Ncgc00159466-03

143. 51339-48-1

144. Ac-18721

145. Cas-28981-97-7

146. C06817

147. D00225

148. 981a977

149. A819702

150. Q319877

151. W-107015

152. Brd-k32398298-001-01-4

153. Alprazolam, European Pharmacopoeia (ep) Reference Standard

154. 8-chloro-1-methyl-6-phenyl-4h-s-triazolo [4,3-a] [1,4] Benzodiazepine

155. 8-chloro-1-methyl-6-phenyl-4h-s-triazolo [4,3-a][1,4] Benzodiazepine

156. 8-chloro-6-phenyl-1-methyl-4h-s-triazolo-[4,3-a][1,4]benzodiazepine

157. (z)-8-chloro-1-methyl-6-phenyl-4h-benzo[f][1,2,4]triazolo[4,3-a][1,4]diazepine

158. 4h-(1,2,4)triazolo(4,3-.alpha.)(1,4)benzodiazepine, 8-chloro-1-methyl-6-phenyl-

159. 8-chloranyl-1-methyl-6-phenyl-4h-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine

160. 8-chloro-1-methyl-6-phenyl-4h-s-triazolo(4,3-.alpha.)(1,4)benzodiazepine

161. Alprazolam Solution, 1 Mg/ml In Methanol, Analytical Standard, For Drug Analysis

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

163. 12-chloro-3-methyl-9-phenyl-2,4,5,8-tetraazatricyclo[8.4.0.0^{2,6}]tetradeca-1(10),3,5,8,11,13-hexaene

164. 1246182-61-5

2.4 Create Date
2005-03-25
3 Chemical and Physical Properties
Molecular Weight 308.8 g/mol
Molecular Formula C17H13ClN4
XLogP32.1
Hydrogen Bond Donor Count0
Hydrogen Bond Acceptor Count3
Rotatable Bond Count1
Exact Mass308.0828741 g/mol
Monoisotopic Mass308.0828741 g/mol
Topological Polar Surface Area43.1 Ų
Heavy Atom Count22
Formal Charge0
Complexity434
Isotope Atom Count0
Defined Atom Stereocenter Count0
Undefined Atom Stereocenter Count0
Defined Bond Stereocenter Count0
Undefined Bond Stereocenter Count0
Covalently Bonded Unit Count1
4 Drug and Medication Information
4.1 Drug Information
1 of 10  
Drug NameAlprazolam
PubMed HealthAlprazolam (By mouth)
Drug ClassesAntianxiety
Drug LabelAlprazolamextended-release tabletscontain alprazolam USP, which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.The chemical name of alprazolam is 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-] [...
Active IngredientAlprazolam
Dosage FormTablet, extended release; Tablet, orally disintegrating; Tablet; Concentrate
RouteOral
Strength1mg/ml; 0.5mg; 2mg; 1mg; 0.25mg; 3mg
Market StatusPrescription
CompanyCorepharma; Vintage Pharms; Anchen Pharms; Mylan Pharms; Amneal Pharms Ny; Actavis Elizabeth; Ani Pharms; Aurobindo Pharma Usa; Actavis Labs Fl; Apotex; Vintage; Dava Intl; Zydus Pharms Usa; Sandoz; Sun Pharma Global; Par Pharm; Mylan; Impax Labs; Roxane

2 of 10  
Drug NameAzor
PubMed HealthAmlodipine/Olmesartan (By mouth)
Drug ClassesAntihypertensive
Active Ingredientolmesartan medoxomil; Amlodipine besylate
Dosage FormTablet
RouteOral
Strengtheq 5mg base; eq 10mg base; 40mg; 20mg
Market StatusPrescription
CompanyDaiichi Sankyo

3 of 10  
Drug NameNiravam
PubMed HealthAlprazolam (By mouth)
Drug ClassesAntianxiety
Drug LabelNIRAVAM (alprazolam orally disintegrating tablets) contains alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds. NIRAVAM is an orally administered formulation of alprazolam which rapidl...
Active IngredientAlprazolam
Dosage FormTablet, orally disintegrating
RouteOral
Strength0.5mg; 1mg; 0.25mg; 2mg
Market StatusPrescription
CompanyUcb

4 of 10  
Drug NameXanax
PubMed HealthAlprazolam (By mouth)
Drug ClassesAntianxiety
Drug LabelXANAX XR Tablets contain alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.The chemical name of alprazolam is 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-] [1,4] benzodiazepine. The m...
Active IngredientAlprazolam
Dosage FormTablet
RouteOral
Strength0.5mg; 1mg; 0.25mg; 2mg
Market StatusPrescription
CompanyPharmacia And Upjohn

5 of 10  
Drug NameXanax xr
Drug LabelXANAX XR Tablets contain alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.The chemical name of alprazolam is 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-] [1,4] benzodiazepine. The m...
Active IngredientAlprazolam
Dosage FormTablet, extended release
RouteOral
Strength0.5mg; 1mg; 2mg; 3mg
Market StatusPrescription
CompanyPharmacia And Upjohn

6 of 10  
Drug NameAlprazolam
PubMed HealthAlprazolam (By mouth)
Drug ClassesAntianxiety
Drug LabelAlprazolamextended-release tabletscontain alprazolam USP, which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.The chemical name of alprazolam is 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-] [...
Active IngredientAlprazolam
Dosage FormTablet, extended release; Tablet, orally disintegrating; Tablet; Concentrate
RouteOral
Strength1mg/ml; 0.5mg; 2mg; 1mg; 0.25mg; 3mg
Market StatusPrescription
CompanyCorepharma; Vintage Pharms; Anchen Pharms; Mylan Pharms; Amneal Pharms Ny; Actavis Elizabeth; Ani Pharms; Aurobindo Pharma Usa; Actavis Labs Fl; Apotex; Vintage; Dava Intl; Zydus Pharms Usa; Sandoz; Sun Pharma Global; Par Pharm; Mylan; Impax Labs; Roxane

7 of 10  
Drug NameAzor
PubMed HealthAmlodipine/Olmesartan (By mouth)
Drug ClassesAntihypertensive
Active Ingredientolmesartan medoxomil; Amlodipine besylate
Dosage FormTablet
RouteOral
Strengtheq 5mg base; eq 10mg base; 40mg; 20mg
Market StatusPrescription
CompanyDaiichi Sankyo

8 of 10  
Drug NameNiravam
PubMed HealthAlprazolam (By mouth)
Drug ClassesAntianxiety
Drug LabelNIRAVAM (alprazolam orally disintegrating tablets) contains alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds. NIRAVAM is an orally administered formulation of alprazolam which rapidl...
Active IngredientAlprazolam
Dosage FormTablet, orally disintegrating
RouteOral
Strength0.5mg; 1mg; 0.25mg; 2mg
Market StatusPrescription
CompanyUcb

9 of 10  
Drug NameXanax
PubMed HealthAlprazolam (By mouth)
Drug ClassesAntianxiety
Drug LabelXANAX XR Tablets contain alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.The chemical name of alprazolam is 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-] [1,4] benzodiazepine. The m...
Active IngredientAlprazolam
Dosage FormTablet
RouteOral
Strength0.5mg; 1mg; 0.25mg; 2mg
Market StatusPrescription
CompanyPharmacia And Upjohn

10 of 10  
Drug NameXanax xr
Drug LabelXANAX XR Tablets contain alprazolam which is a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds.The chemical name of alprazolam is 8-chloro-1-methyl-6-phenyl-4H-s-triazolo [4,3-] [1,4] benzodiazepine. The m...
Active IngredientAlprazolam
Dosage FormTablet, extended release
RouteOral
Strength0.5mg; 1mg; 2mg; 3mg
Market StatusPrescription
CompanyPharmacia And Upjohn

4.2 Therapeutic Uses

Anti-Anxiety Agents; GABA Modulators; Hypnotics and Sedatives

National Library of Medicine's Medical Subject Headings. Alprazolam. Online file (MeSH, 2016). Available from, as of October 28, 2016: https://www.nlm.nih.gov/mesh/2016/mesh_browser/MBrowser.html


Xanax Tablets (alprazolam) are indicated for the management of anxiety disorder (a condition corresponding most closely to the APA Diagnostic and Statistical Manual (DSM-IIIR) diagnosis of generalized anxiety disorder) or the short-term relief of symptoms of anxiety. Anxiety or tension associated with the stress of everyday life usually does not require treatment with an anxiolytic. /Included in US product labeling/

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Xanax is also indicated for the treatment of panic disorder, with or without agoraphobia. /Included in US product labeling/

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


VET: /Alprazolam/ may be useful in cats to treat anxiety disorders and unlike oral diazepam in cats, has not been implicated in causing liver failure.

Plumb D.C. Veterinary Drug Handbook. 8th ed. (pocket). Ames, IA: Wiley-Blackwell, 2015., p. 45


VET: Alprazolam may be useful for adjunctive therapy in anxious, aggressive dogs or in those demonstrating panic reactions. It is mose effective when used in advance of a triggering event. (NOTE: Some clinicians believe that benzodiazepines are contraindicated in aggressive dogs as anxiety may actually restrain the animal from aggressive tendencies.)

Plumb D.C. Veterinary Drug Handbook. 8th ed. (pocket). Ames, IA: Wiley-Blackwell, 2015., p. 45


4.3 Drug Warning

Episodes of mania and hypomania have been reported in depressed patients receiving alprazolam.

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2004. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2004 (Plus Supplements)., p. 2381


Pregnancy risk category: D /POSITIVE EVIDENCE OF RISK. Studies in humans, or investigational or post-marketing data, have demonstrated fetal risk. Nevertheless, potential benefits from the use of the drug may outweigh the potential risk. For example, the drug may be acceptable if needed in a life-threatening situation or serious disease for which safer drugs cannot be used or are ineffective./

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Benzodiazepines can potentially cause fetal harm when administered to pregnant women. If Xanax is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus. Because of experience with other members of the benzodiazepine class, Xanax is assumed to be capable of causing an increased risk of congenital abnormalities when administered to a pregnant woman during the first trimester. Because use of these drugs is rarely a matter of urgency, their use during the first trimester should almost always be avoided. The possibility that a woman of childbearing potential may be pregnant at the time of institution of therapy should be considered. Patients should be advised that if they become pregnant during therapy or intend to become pregnant they should communicate with their physicians about the desirability of discontinuing the drug.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Safety and efficacy of alprazolam have not been established in children younger than 18 years of age.

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2004. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2004 (Plus Supplements)., p. 2381


For more Drug Warnings (Complete) data for ALPRAZOLAM (16 total), please visit the HSDB record page.


4.4 Drug Indication

Alprazolam is indicated for the acute treatment of generalized anxiety disorder in adults. Alprazolam is also indicated, either as a standard or extended-release formulation, for the treatment of panic disorder with or without agoraphobia in adults. Alprazolam may also be prescribed off-label for insomnia, premenstrual syndrome, and depression.


FDA Label


5 Pharmacology and Biochemistry
5.1 Pharmacology

Alprazolam is a benzodiazepine that binds -aminobutyric acid (GABA) type-A receptors (GABAARs) to enhance their inhibitory effect on neurotransmission, specifically in the brain. Concomitant use with opioids may result in profound sedation, respiratory depression, coma, and death; patients taking benzodiazepines and opioids concurrently may require lower doses of one or both medications, depending on their clinical situation. Patients with pre-existing impaired respiratory function are at increased risk of adverse effects including death during treatment with benzodiazepines. In addition, due to its CNS depressant effects, patients taking alprazolam should avoid operating heavy machinery or driving and should avoid other CNS depressants such as alcohol. As with other benzodiazepines, alprazolam carries a risk of abuse, misuse, and addiction, which is higher in predisposed individuals and may require strict monitoring. Cessation of therapy may result in acute or protracted withdrawal symptoms, which may be life-threatening; the patient dose should be gradually tapered whenever discontinuation or reduced dosage are necessary. Newborns born to mothers using alprazolam later in pregnancy may suffer from sedation and withdrawal symptoms. As CYP3A is required for the initial step in alprazolam metabolism, alprazolam is contraindicated in patients taking strong CYP3A inhibitors, such as ketoconazole and itraconazole; milder CYP3A inhibitors still necessitate alprazolam dosage adjustments. Lastly, benzodiazepines may have negative effects, such as panic disorders, increased suicide incidence, and episodes of mania/hypomania, in patients suffering from depression.


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.)


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.)


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.)


5.3 FDA Pharmacological Classification
5.3.1 Active Moiety
ALPRAZOLAM
5.3.2 FDA UNII
YU55MQ3IZY
5.3.3 Pharmacological Classes
Benzodiazepines [CS]; Benzodiazepine [EPC]
5.4 ATC Code

N05BA12

S76 | LUXPHARMA | Pharmaceuticals Marketed in Luxembourg | Pharmaceuticals marketed in Luxembourg, as published by d'Gesondheetskeess (CNS, la caisse nationale de sante, www.cns.lu), mapped by name to structures using CompTox by R. Singh et al. (in prep.). List downloaded from https://cns.public.lu/en/legislations/textes-coordonnes/liste-med-comm.html. Dataset DOI:10.5281/zenodo.4587355


N - Nervous system

N05 - Psycholeptics

N05B - Anxiolytics

N05BA - Benzodiazepine derivatives

N05BA12 - Alprazolam


5.5 Absorption, Distribution and Excretion

Absorption

Alprazolam administered orally is rapidly absorbed in the gastrointestinal tract, reaching Cmax in about 1.8 (1-2) hours. Absorption is high, resulting in an oral bioavailability of 84-91%. A 1 mg oral dose results in a Cmax of 12-22 g/L. The extended-release formulation of alprazolam (XANAX XR) has similar absorption, bioavailability, and pharmacokinetics as the standard release, with the exception that the Tmax is ~10 hours compared to 1-2 hours. Temporal dosing alters these parameters, with Cmax increasing by 30% and Tmax decreasing by one hour when dosed at night as opposed to in the morning. Food has an effect on alprazolam absorption; a high-fat meal up to two hours before dosing increases the Cmax by ~25% and either a reduction (food consumed immediately prior to dosing) or increase (food consumed after dosing) of ~1/3 in Tmax. Neither the AUC nor half-life are appreciably affected by eating.


Route of Elimination

Alprazolam is mainly eliminated in the urine. A large portion of the dose is eliminated as unmetabolized alprazolam. <10% of the dose is eliminated as alpha-hydroxy-alprazolam and 4-hydroxy-alprazolam.


Volume of Distribution

Alprazolam has a volume of distribution following oral administration of 0.8-1.3L/kg. Alprazolam crosses the blood-brain barrier.


Clearance

A 0.8 mg oral dose of alprazolam had a clearance of 0.90 0.21 mL/min/kg, which increased to 2.13 0.54 mL/min/kg when coadministered with the strong CYP3A4 inducer carbamazepine. Other studies have demonstrated a clearance of 0.70-1.5mL/min/kg.


In vitro, alprazolam is bound (80 percent) to human serum protein. Serum albumin accounts for the majority of the binding.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Alprazolam and its metabolites are excreted primarily in the urine.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Following oral administration, alprazolam is readily absorbed. Peak concentrations in the plasma occur in 1 to 2 hours following administration. Plasma levels are proportionate to the dose given; over the dose range of 0.5 to 3.0 mg, peak levels of 8.0 to 37 ng/mL were observed.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


The newborn of a mother reporting alprazolam use during pregnancy presented with respiratory distress and clinical features consistent with neonatal withdrawal syndrome or neonatal sepsis of vertical transmission. Alprazolam and its main metabolite (alpha-hydroxyalprazolam) were detected in cord serum, neonatal urine and also in neonatal hair, meconium and placenta, accounting for both acute and chronic exposure to this benzodiazepine during intrauterine life. ...

PMID:17453885 Garcia-Algar O et al; Clin Toxicol (Phila) 45 (3): 295-8 (2007)


5.6 Metabolism/Metabolites

Alprazolam is metabolized to less effective metabolites by various CYPs including CYP3A4, CYP3A5, CYP3A7, and CYP2C9. The majority of alprazolam metabolism is mediated by hydroxylation via CYP3As. 4-hydroxyalprazolam has 20% the binding affinity of the parent drug, alpha-hydroxyalprazolam has 66% the affinity, and the benzophenone metabolite has <1% the affinity.


Alprazolam, an anti-anxiety agent, is metabolized in rat and human liver by P4503A1 and P4503A4 respectively, to 4-hydroxy alprazolam (4-OHALP, pharmacologically less active) and alpha-hydroxy alprazolam (alpha-OHALP, pharmacologically more active). We examined P450 mediated metabolism of alprazolam by rat and human brain microsomes and observed that the relative amount of alpha-OHALP formed in brain was higher than liver. This biotransformation was mediated by a P450 isoform belonging to P4503A subfamily, which is constitutively expressed in neuronal cells in rat and human brain. The formation of larger amounts of alpha-OHALP in neurons points to local modulation of pharmacological activity in brain, at the site of action of the anti-anxiety drug. Since hydroxy metabolites of alprazolam are hydrophilic and not easily cleared through blood-CSF barrier, alpha-OHALP would potentially have a longer half-life in brain.

PMID:12196913 Pai HV et al; Pharmacogenomics J 2 (4): 243-58 (2002)


Alprazolam is extensively metabolized in humans, primarily by cytochrome P450 3A4 (CYP3A4), to two major metabolites in the plasma: 4-hydroxyalprazolam and a-hydroxyalprazolam. A benzophenone derived from alprazolam is also found in humans. Their half-lives appear to be similar to that of alprazolam. The plasma concentrations of 4-hydroxyalprazolam and a-hydroxyalprazolam relative to unchanged alprazolam concentration were always less than 4%. The reported relative potencies in benzodiazepine receptor binding experiments and in animal models of induced seizure inhibition are 0.20 and 0.66, respectively, for 4-hydroxyalprazolam and a-hydroxyalprazolam. Such low concentrations and the lesser potencies of 4-hydroxyalprazolam and a-hydroxyalprazolam suggest that they are unlikely to contribute much to the pharmacological effects of alprazolam. The benzophenone metabolite is essentially inactive.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Alprazolam has known human metabolites that include 4-Hydroxyalprazolam and Beta-Hydroxyalprazolam.

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


5.7 Biological Half-Life

Alprazolam has a mean plasma elimination half-life of 11.2 hours in healthy patients (range 6.3-26.9 hours). The mean half-life is 16.3 hours (range 9.0-26.9 hours) in the elderly, 21.8 hours (range 9.9-40.4 hours) in obese patients, and 19.7 hours (range 5.8-65.3 hours) in patients with alcoholic liver disease. The half-life is 25% higher in Asian patients compared to Caucasians. Other studies have shown the half-life to be 9-16h. The extended-release formulation has a half-life of 10.7-15.8 hours in healthy adult patients.


Using a specific assay methodology, the mean plasma elimination half-life of alprazolam has been found to be about 11.2 hours (range: 6.3-26.9 hours) in healthy adults.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


5.8 Mechanism of Action

Neurotransmission relies on excitatory and inhibitory signalling. -aminobutyric acid (GABA) type-A receptors (GABAARs) are members of the pentameric ligand-gated ion channel (PLGIC) superfamily located synaptically and perisynaptically to mediate phasic inhibition and extrasynaptically to mediate tonic inhibition. GABAARs comprise a variety of subunits from a homologous family whose members are named based on sequence identity as one of 1-6, 1-3, 1-3, , , , , and 1-3. Each subunit possesses an extracellular (ECD), transmembrane (TMD), and intracellular (ICD) domain; inter-subunit interfaces are the primary points of neurotransmitter and modulator binding, described by coordination of the principal (+) and complementary (-) sites in each subunit. Binding of GABA to GABAARs induces pore opening, rapid flow of chloride ions, and synaptic hyperpolarization, which in turn manifests as an inhibitory signal. The most prevalent GABAARs _in vivo_ are the 122 receptors, which contain both GABA (+/-) and benzodiazepine (BZD, +/-) binding sites in the intersubunit interfaces of the relevant subunits. In general, any receptors containing an x/z interface, where x = 1-3,5 and z = 1-3, have potential high-affinity BZD binding sites, although small sequence differences between subunits may alter binding affinity to individual molecules. The 4 and 6 subunits, in which an otherwise conserved histidine is replaced by arginine, do not bind traditional BZD ligands such as diazepam and hence are considered "diazepam-insensitive". GABA binding results in a series of conformational changes in the ECDs of GABAAR subunits, "locking" each to its neighbouring - interface. The binding of alprazolam in the high-affinity BZD site stabilizes the +/- interface and facilitates the conformational changes that lead to pore opening, hence functioning as a positive allosteric modulator. The exact manner in which GABAAR allosteric modulation mediates the therapeutic and unwanted effects of benzodiazepines remains unclear. Earlier studies suggested that the primary factor was the subunit composition, with 1-containing receptors mediating the sedative effects, 2/3-containing receptors the anxiolytic effects, and 5-containing receptors the memory effects of benzodiazepines. More recent studies suggest a more complex set of factors including subunit composition, physiological location, neuronal circuit, and nerve cell type. To further complicate matters, there may be up to five distinct BZD binding sites on GABAARs, with site 1 corresponding to the classical high-affinity +/- interface. The effects of binding at sites 2-4 are not fully understood and likely impart greater complexity to benzodiazepine pharmacological action.


In animals, benzodiazepines protect against seizures induced by electrical stimulation and by pentylenetetrazol; benzodiazepines appear to act, at least partly, by augmenting presynaptic inhibition. The drugs suppress the spread of seizure activity but do not abolish the abnormal discharge from a focus in experimental models of epilepsy. In usual doses, benzodiazepines appear to have very little effect on the autonomic nervous system, respiration, or the cardiovascular system. /Benzodiazepines/

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2004. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2004 (Plus Supplements)., p. 2379


CNS agents of the 1,4 benzodiazepine class presumably exert their effects by binding at stereo specific receptors at several sites within the central nervous system. Their exact mechanism of action is unknown. Clinically, all benzodiazepines cause a dose-related central nervous system depressant activity varying from mild impairment of task performance to hypnosis.

NIH; DailyMed. Current Medication Information for Xanax (Alprazolam) Tablet (Updated: October 2016). Available from, as of October 28, 2016: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=388e249d-b9b6-44c3-9f8f-880eced0239f


Anxiolytic and possibly paradoxical CNS stimulatory effects of benzodiazepines are postulated to result from release of previously suppressed responses (disinhibition). After usual doses of benzodiazepines for several days, the drugs cause a moderate decrease in rapid eye movement (REM) sleep. REM rebound does not occur when the drugs are withdrawn. Stage 3 and 4 sleep are markedly reduced by usual doses of the drugs; the clinical importance of these sleep stage alterations has not been established. /Benzodiazepines/

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2004. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2004 (Plus Supplements)., p. 2379


Benzodiazepines appear to produce skeletal muscle relaxation predominantly by inhibiting spinal polysynaptic afferent pathways, but the drugs may also inhibit monosynaptic afferent pathways. The drugs may inhibit monosynaptic and polysynaptic reflexes by acting as inhibitory neuronal transmitters or by blocking exitatory synaptic transmission. The drugs may also directly depress motor nerve and muscle function. /Benzodiazepines/

McEvoy, G.K. (ed.). American Hospital Formulary Service- Drug Information 2004. Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2004 (Plus Supplements)., p. 2379