Anxiolytics: Pharmacology, Rational Use and Dependence-Safe Prescribing
Anxiolytics reduce distressing anxiety symptoms, but they are not all interchangeable. Some provide rapid relief of acute autonomic arousal; others treat the underlying anxiety disorder gradually; some are mainly short-term adjuncts. The safest plan combines diagnostic assessment, psychological care and carefully selected medicine rather than indefinite sedation.
Learning outcomes
- Classify major anxiolytic drug groups.
- Explain benzodiazepine GABA-A pharmacology and its risks.
- Choose treatment for acute anxiety, panic, GAD and medically ill patients safely.
- Recognise withdrawal, overdose and dangerous sedative combinations.
1. Assess before medicating
Anxiety may be a symptom of panic disorder, generalised anxiety disorder, depression, PTSD, psychosis, substance intoxication/withdrawal, hyperthyroidism, arrhythmia, asthma, hypoglycaemia, pain or a social crisis. Assess onset, triggers, sleep, mood, suicide risk, alcohol and other drug use, medications, pregnancy and red flags. Chest pain, severe dyspnoea, syncope, delirium, severe agitation or suspected withdrawal needs medical assessment; do not label a physiological emergency as “anxiety.”
2. Main drug groups
| Group | Examples | Place in care |
|---|---|---|
| Benzodiazepines | Diazepam, lorazepam, alprazolam, clonazepam, midazolam | Rapid symptom control, acute seizures, alcohol withdrawal and procedural/acute agitation contexts. Shortest effective course for anxiety. |
| SSRIs/SNRIs | Sertraline, fluoxetine, escitalopram, venlafaxine, duloxetine | Longer-term treatment for several anxiety disorders; delayed onset and possible early activation. |
| Buspirone | 5-HT1A partial agonist | Selected GAD; not useful as immediate rescue and does not produce benzodiazepine-like dependence. |
| Antihistamine/other sedating agents | Hydroxyzine and context-specific agents | Selected short-term use; sedation and anticholinergic burden matter. |
| Beta blockers | Propranolol | May reduce peripheral symptoms in selected performance anxiety; not a primary treatment for GAD/panic and is unsafe in some airway/cardiac disease. |
3. Benzodiazepines in depth
Benzodiazepines bind an allosteric site on the GABA-A receptor and increase the frequency of chloride-channel opening in the presence of GABA, enhancing inhibitory neurotransmission. They cause anxiolysis, sedation, muscle relaxation, anticonvulsant effect and anterograde amnesia. They differ in onset, half-life and active metabolites; these differences matter in older adults, liver disease, withdrawal and next-day impairment.
Dependence and respiratory depression
Tolerance and physical dependence can develop, especially with daily use. Abrupt cessation after prolonged exposure can cause rebound anxiety, insomnia, tremor, perceptual disturbance, seizures and delirium. Benzodiazepines combined with opioids, alcohol or other sedatives can cause fatal respiratory depression. Avoid routine co-prescribing, use the lowest effective dose for the shortest time, check other sedatives and provide a clear stop/taper plan.
4. Overdose and withdrawal
Isolated benzodiazepine overdose often causes drowsiness, ataxia and slurred speech, but co-ingestion changes risk dramatically. Assess airway, breathing, consciousness, glucose, trauma and co-ingestants; provide supportive care and urgent escalation when respiratory depression is present. Flumazenil can precipitate seizures/withdrawal and is not a routine antidote for undifferentiated overdose or chronic users; use only under expert protocol. For withdrawal, avoid abrupt stopping; individualise a supervised gradual taper and treat alcohol/substance-use disorder when present.
5. SSRIs/SNRIs and psychological care
For persistent anxiety disorders, CBT and other evidence-based psychological interventions are central. SSRIs/SNRIs often need several weeks for benefit and may transiently increase jitteriness or sleep disruption. Start and review carefully; screen for bipolar disorder, suicide risk, interactions and serotonin syndrome. A short benzodiazepine bridge is occasionally used under close review, but it should never silently become a long-term prescription.
6. Special populations
- Older adults: increased falls, delirium, cognitive impairment and prolonged sedation; avoid or minimise benzodiazepines.
- Pregnancy/breastfeeding: risk-benefit assessment and specialist/obstetric guidance are needed; do not stop effective psychiatric treatment abruptly without review.
- Liver/respiratory disease: prolonged sedation and hypoventilation risk; select and monitor carefully.
- Substance-use disorder: assess dependence, diversion and withdrawal; coordinate addiction/mental-health care.
OSCE points
- Rule out medical causes and suicidality before offering medicine.
- Explain that benzodiazepines are short-term and impair driving/alcohol safety.
- State the opioid–alcohol–benzodiazepine respiratory-depression warning explicitly.
- For long-term GAD/panic, combine psychological treatment with an appropriate maintenance plan and follow-up.
Knowledge check
- How do benzodiazepines enhance GABA-A signalling?
- Why is alcohol plus diazepam dangerous?
- Why is flumazenil not routinely used in overdose?
- Which treatment is suitable for immediate relief versus longer-term GAD treatment?
- List four benzodiazepine withdrawal features.
