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Other information

Indication
For the treatment or management of panic disorder, with or without agoraphobia

Pharmacology
Alprazolam, a benzodiazepine, is used to treat panic disorder and anxiety disorder. Unlike chlordiazepoxide, clorazepate, and prazepam, alprazolam has a shorter half-life and yields metabolites with minimal activity. Like other triazolo benzodiazepines such as triazolam, alprazolam may have significant drug interactions involving the hepatic cytochrome P-450 3A4 isoenzyme.

Mechanism Of Action
Benzodiazepines bind nonspecifically to benzodiazepine receptors BNZ1, which mediates sleep, and BNZ2, which affects affects muscle relaxation, anticonvulsant activity, motor coordination, and memory. As benzodiazepine receptors are thought to be coupled to gamma-aminobutyric acid-A (GABA_A) receptors, this enhances the effects of GABA by increasing membrane that prevents further excitation of the cell.

Drug Category
Anti-anxiety Agents; Hypnotics and Sedatives; Benzodiazepines; GABA Modulators;

Brand Names/Synonyms
Alplax; Alprazolam; Alpronax; Bestrol; Cassadan; Constan; D 65MT; Esparon; Frontal; Intensol; Niravam; TUS-1; Tafil; Trankimazin; Tranquinal; Xanax; Xanax Xr; Xanor

Dosage Forms
TABLET

Absorption
Following oral administration Benzodiazepines are well absorbed from the gastrointestinal tract, usually within 1 to 2 hours. Following intramuscular administration _ Lorazepam absorption is rapid and complete, whereas chlordiazepoxide and diazepam absorption may be slow and erratic, depending upon the site of administration . When diazepam is injected into the deltoid muscle, absorption is usually rapid and complete . Following rectal administration _ Absorption of diazepam rectal solution and rectal gel is rapid.

Interactions
-->Interactions for Alprazolam:

The benzodiazepines, including alprazolam, produce additive CNS depressant effects when co-administered with other psychotropic medications, anticonvulsants, antihistaminics, ethanol, and other drugs which themselves produce CNS depression.

The steady state plasma concentrations of imipramine and desipramine have been reported to be increased an average of 31% and 20%, respectively, by the concomitant administration of alprazolam tablets in doses up to 4 mg/day. The clinical significance of these changes is unknown.

Drugs That Inhibit Alprazolam Metabolism Via Cytochrome P450 3A: The initial step in alprazolam metabolism is hydroxylation catalyzed by cytochrome P450 3A (CYP 3A). Drugs which inhibit this metabolic pathway may have a profound effect on the clearance of alprazolam .

Drugs Demonstrated to be CYP 3A Inhibitors of Possible Clinical Significance on the Basis of Clinical Studies Involving Alprazolam (caution is recommended during coadministration with alprazolam):

Fluoxetine: Coadministration of fluoxetine with alprazolam increased the maximum plasma concentration of alprazolam by 46%, decreased clearance by 21%, increased half-life by 17%, and decreased measured psychomotor performance.

Propoxyphene: Coadministration of propoxyphene decreased the maximum plasma concentration of alprazolam by 6%, decreased clearance by 38%, and increased half-life by 58%.

Oral Contraceptives: Coadministration of oral contraceptives increased the maximum plasma concentration of alprazolam by 18%, decreased clearance by 22%, and increased half-life by 29%.

Drugs and other substances demonstrated to be CYP 3A inhibitors on the basis of clinical studies involving benzodiazepines metabolized similarly to alprazolam or on the basis of in vitro studies with alprazolam or other benzodiazepines (caution is recommended during coadministration with alprazolam): Available data from clinical studies of benzodiazepines other than alprazolam suggest a possible drug interaction with alprazolam for the following: diltiazem, isoniazid, macrolide antibiotics such as erythromycin and clarithromycin, and grapefruit juice. Data from in vitro studies of alprazolam suggest a possible drug interaction with alprazolam for the following: sertraline and paroxetine. Data from in vitro studies of benzodiazepines other than alprazolam suggest a possible drug interaction for the following: ergotamine, cyclosporine, amiodarone, nicardipine, and nifedipine. Caution is recommended during the coadministration of any of these with alprazolam.

Chemical IUPAC Name
8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazepine

Chemical Formula
C17H13ClN4

Half Life
6.3-26.9 hours (average = 11.2 hrs)

Drug Type
Approved Drug

# Accession No
APRD00280

CAS Registry Number
28981-97-7