Alprazolam: A fast-acting benzodiazepine for anxiety

What it is

Alprazolam is a triazolo benzodiazepine with rapid absorption and an intermediate half-life (11–16 hours). It is effective in acute anxiety and panic disorder and starts working in 15–30 minutes, which makes it popular, but it also carries a high risk of dependence.

Guidelines limit its use to short periods —the product information sets a maximum of weeks, withdrawal included— and as a bridge while the core treatment (an SSRI and psychotherapy) takes effect. It is a prescription medicine and is controlled because of its risk of misuse.

Mechanism of action

It enhances:

GABAergic effects: it binds to GABA-A receptors, increasing their affinity for GABA
It hyperpolarises neurones, reducing excitability
Anxiolytic, sedative, muscle-relaxant and anticonvulsant (all through GABA)

At the counter

When to recommend it

Acute panic attack
Severe acute anxiety
Agoraphobia with panic attacks
As a bridge when starting an SSRI, for a few weeks

When not to

History of alcohol or drug misuse (caution)
Pregnancy: avoid, especially in the first trimester and near the end (neonatal withdrawal syndrome)
Untreated sleep apnoea
Severe respiratory failure or myasthenia gravis
As the only treatment for depression

What to say at the counter. When supplying it, three lines: 'no alcohol', 'don't drive until you know how it affects you' and 'don't stop it suddenly: if it has to be stopped, it's tapered with your doctor.' And if they have been taking it for months, it is a good moment to suggest reviewing it with their doctor.

Warnings

Important Dependence and tolerance: they develop quickly (2–4 weeks). High risk of misuse. Severe withdrawal if stopped suddenly.
Important Cognitive effects: anterograde amnesia (not remembering what happened after taking it), disinhibition, risky behaviour.
Caution Drowsiness, unsteadiness, confusion.
Caution Paradoxical reaction: in some people (especially young people and older people), increased anxiety or agitation.

Pharmacokinetics

Absorption: Very rapid and complete absorption. Bioavailability of 80–90%. Onset at 15–30 minutes, peak at 1–2 hours.
Distribution: Rapid distribution into the CNS (fat-soluble). Protein binding of 80%. It crosses the placenta and the blood–brain barrier.
Metabolism: Hepatic metabolism by conjugation and oxidation (CYP3A4). It produces active metabolites (α-hydroxy-alprazolam).
Elimination: Renal elimination of metabolites. Half-life of 12–15 hours, with active metabolites extending the effect.

Alprazolam vs sertraline

Aspect	Alprazolam	Sertraline (SSRI)
Onset of effect	Fast (15–30 min)	Slow (2–4 weeks)
Dependence	High risk	No
Long-term use	NOT recommended	Recommended
Acute anxiety	Excellent	Not effective at first
Treatment role	Bridge (a few weeks)	Long-term maintenance

Alprazolam only for short periods. Sertraline for chronic anxiety. At the start they can be combined, on medical advice.

Self-assessment

Three questions. When you check your answers you will see the explanation for each one.

What is the main problem with alprazolam as a long-term treatment? It is very expensive Dependence and tolerance develop quickly. It is NOT recommended for long-term use It does not work
A patient with panic disorder needs treatment. What is the strategy? Nothing, panic goes away on its own Alprazolam indefinitely Sertraline (SSRI) as the core + alprazolam for a few weeks for the initial acute anxiety
What can happen if alprazolam is stopped suddenly after weeks of use? Nothing, it is eliminated within hours Just a little drowsiness A withdrawal syndrome that can be serious (rebound anxiety, insomnia and even seizures)

Training content. It does not replace the summary of product characteristics or clinical judgement.

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