Alprazolam
Alprazolam is a short to intermediate-acting benzodiazepine used in adults for the short-term management of anxiety disorders and panic disorder. It potentiates GABA-A signalling, with a relevant risk of dependence on prolonged use.
- Chemical formula
- C17H13ClN4
- CAS number
- 28981-97-7
- ATC code
- N05BA12
- Molecular weight
- 308.76 g/mol
- Drug class
- Benzodiazepine
- Also known as
- U-31889, Alprazolam
What is it?
Alprazolam is a triazolobenzodiazepine first introduced in 1981 by Upjohn. It became one of the most widely prescribed benzodiazepines for anxiety and panic disorder. It is supplied as immediate-release and extended-release tablets and as oral solutions, and is dispensed only on prescription in most jurisdictions because of its potential for misuse and dependence. According to current clinical guidelines, prescription is restricted to short-term use under specialist supervision.
Mechanism of action
Alprazolam binds to the benzodiazepine site of the GABA-A receptor, allosterically enhancing the action of the inhibitory neurotransmitter gamma-aminobutyric acid. Increased chloride conductance hyperpolarises neurons in the central nervous system, producing anxiolytic, sedative, hypnotic, anticonvulsant and muscle-relaxant effects. Compared with other benzodiazepines, alprazolam has a relatively rapid onset and a comparatively short half-life, which contributes to both its clinical effects and its dependence potential.
Pharmacokinetics
Alprazolam is well absorbed after oral administration, with peak plasma concentrations reached within one to two hours for the immediate-release formulation. Plasma protein binding is approximately 80%. The drug is metabolised in the liver mainly by CYP3A4 to several active metabolites of low potency. The terminal half-life ranges from 6 to 27 hours. Renal excretion of metabolites is the main elimination pathway. Hepatic impairment, elderly age and CYP3A4 inhibitors increase exposure.
Indications
Alprazolam is approved in adults for the short-term treatment of generalised anxiety disorder and panic disorder with or without agoraphobia. According to international guidelines, prescription should be limited to the lowest effective dose for the shortest period needed, typically two to four weeks, with periodic reassessment. Alprazolam is not indicated for primary insomnia, depression without anxiety, or in paediatric populations outside specific specialist settings.
Safety profile
Common adverse effects include sedation, drowsiness, dizziness, dry mouth, memory impairment and ataxia. Cognitive and psychomotor performance is impaired, particularly when combined with alcohol or other CNS depressants such as opioids, where the combination significantly increases the risk of severe sedation and respiratory depression. Tolerance, physical dependence and withdrawal symptoms are well documented. According to the prescribing information, treatment should be tapered gradually and never stopped abruptly; concurrent use with strong CYP3A4 inhibitors requires dose adjustment.
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Frequently asked questions
How quickly does alprazolam work? ▾
Alprazolam typically begins to take effect within 30 to 60 minutes after oral administration of an immediate-release tablet, with peak plasma concentrations reached at around one to two hours. Onset is faster on an empty stomach. Subjective relief of anxiety symptoms can be perceived during this time. According to the prescribing information, the rapid onset contributes to its potential for misuse, particularly when used outside the prescribed schedule.
How long can alprazolam be taken? ▾
Most clinical guidelines recommend short-term use of alprazolam, typically two to four weeks, because of the risk of physical dependence, tolerance and withdrawal symptoms on chronic use. Longer durations are sometimes considered in selected cases under specialist supervision, with regular reassessment. According to the prescribing information, abrupt discontinuation should be avoided and a gradual tapering schedule is preferred.
Can alprazolam be combined with alcohol? ▾
No. Combining alprazolam with alcohol significantly increases the risk of severe sedation, respiratory depression, cognitive impairment and accidents. Concomitant use with opioids carries similar risks and is identified as a major contributor to overdose mortality in several countries. According to the prescribing information, patients should avoid alcohol during treatment and disclose all concomitant medications to the prescriber.
What happens if alprazolam is stopped abruptly? ▾
Abrupt discontinuation after sustained use can cause withdrawal symptoms including rebound anxiety, insomnia, tremor, palpitations, sweating and, rarely, seizures. The risk increases with higher doses, longer duration of treatment and short-acting agents like alprazolam. According to the prescribing information, discontinuation should follow a gradual tapering schedule designed by the prescriber, often over weeks to months.
What are the main contraindications for alprazolam? ▾
Alprazolam is contraindicated in known hypersensitivity to benzodiazepines, in narrow-angle glaucoma, in severe respiratory insufficiency and in concurrent use with strong CYP3A4 inhibitors such as itraconazole or ketoconazole. Caution is required in older adults, in hepatic impairment, in patients with substance use disorders and during pregnancy and breastfeeding. According to the prescribing information, the medical history must be reviewed by a clinician before any prescription.
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