Anxiolytics and hypnotics

Fellowship viva language is concrete: half-life maps, agent-level doses, written exit plans, Beers-listed elderly harm, and when not to reach for alprazolam. Long-term anxiety control is SSRI/SNRI plus psychological therapy; GABAergic drugs are bridges, crisis tools, or specialised exceptions — not lifestyle maintenance.[13][14][5]

Definition and classification

An anxiolytic reduces pathological anxiety; a hypnotic promotes sleep onset or maintenance. Many GABA-A modulators do both in a dose-dependent way. Dependence-capable sedative-hypnotic-anxiolytic prescribing is a public-health and exam problem: high use, especially in older adults, with limited long-term benefit for primary insomnia.[5][26][7]

Classification by mechanism and half-life beats brand lists in the exam room.[1][13][28]

Mechanisms — viva core

Benzodiazepines. Bind the interface of α/γ subunits of GABA-A receptors, increasing frequency of chloride channel opening when GABA is present — positive allosteric modulation, not direct agonists. Teaching model: α1-rich circuits lean sedation/amnesia/anticonvulsant effects; α2/3 lean anxiolysis; α5 relates to cognitive effects. Tolerance develops faster to sedation/hypnosis than to anxiolysis; withdrawal produces rebound hyperexcitability (anxiety, insomnia, autonomic arousal, seizures).[1][3][5]

Z-drugs. Chemically non-benzodiazepine but act at the BZ site of GABA-A receptors with relative α1 preference in teaching narratives. They are not free of dependence, complex sleep behaviours, falls, or driving impairment. Toxicological reviews emphasise residual CNS depression and performance risk.[28][7][1]

Buspirone. 5-HT1A partial agonism; anxiolytic effect is delayed (often framed as 2–4 weeks). No GABA-A PAM activity — cannot substitute for benzodiazepines in withdrawal. Cochrane azapirone evidence supports efficacy versus placebo in GAD with a different adverse-effect profile from benzodiazepines.[22][13]

Pregabalin. Binds α2δ subunit of voltage-gated calcium channels, reducing excitatory neurotransmitter release. Multiple placebo-controlled GAD trials (including comparisons with alprazolam) support anxiolytic efficacy; expect dizziness, somnolence, weight gain/oedema, and growing concern about misuse in vulnerable populations.[17][18][19]

Hydroxyzine. Histamine H1 antagonism produces sedation and anxiolysis without the classical benzodiazepine dependence pathway. A three-month double-blind GAD study and Cochrane review support a role, limited by anticholinergic burden and sedation — especially in older adults.[20][21]

Melatonin. MT1/MT2 agonism with modest effects on sleep latency and total sleep time in meta-analyses — useful circadian/insomnia adjunct framing, not a high-potency hypnotic substitute for CBT-I.[23][24][16]

Epidemiology and harm landscape

Benzodiazepine exposure is common in population datasets; US analyses show substantial use with concentration in older adults — exactly the group with the worst risk–benefit ratio for sedative-hypnotics.[26][6] Meta-analysis in older people with insomnia found sedative-hypnotics improve sleep modestly but increase adverse cognitive and psychomotor events, including falls risk framing used across geriatrics curricula.[7] Concurrent prescription opioids and benzodiazepines associate with overdose in large retrospective analyses — a non-negotiable interaction exam pearl.[25] Observational work also links anxiolytic/hypnotic prescriptions with mortality hazards; treat long-term automatic renewals as a quality and safety problem, not neutral maintenance.[5]

Half-life map and agent selection (benzodiazepines)

LOT teaching (hepatic impairment): prefer lorazepam, oxazepam, temazepam — conjugation pathways with fewer active oxidative metabolites — when liver disease is relevant.[2][1]

Typical adult oral orientation anchors (always check current product information; lower starts in older adults; individualise): dose ranges below are teaching scaffolds from clinical sources and guidelines, not a substitute for local product information.[2][13][15]

Dose tables are exam orientation, not a substitute for local product information.[2][13][15][17][20]

When short-term GABA cover is justified

Legitimate short-term contexts (exam structure): severe acute anxiety or panic bridging while an SSRI/SNRI is started; time-limited severe insomnia after stimulus control/sleep hygiene and when CBT-I access is delayed; alcohol withdrawal protocols (owned by addiction topics); procedural sedation/agitation pathways (owned by emergency topics); selected specialist indications (e.g. catatonia adjunct — pointer). BAP anxiety guidance places SSRIs/SNRIs and psychological therapies as durable treatments; benzodiazepines are not the long-term default for GAD/panic.[13][14]

Insomnia: AASM pharmacologic guidelines and BAP sleep consensus prioritise behavioural treatment; hypnotic medicines, if used, are adjunctive and time-limited, not indefinite renewals.[15][16]

Non-GABAergic options for anxiety when tablets are needed without benzodiazepine dependence pathway (buspirone, pregabalin, hydroxyzine as examined alternatives to chronic GABA cover):

• Buspirone — GAD evidence as azapirone class; delayed onset; good for patients who cannot risk GABAergic dependence if they can wait weeks.[22]
• Pregabalin — multiple positive GAD RCTs including fixed-dose and alprazolam comparator designs.[17][18][19]
• Hydroxyzine — short-to-medium term symptomatic anxiolysis with H1 mechanism; Cochrane supports limited but real efficacy data.[20][21] Non-GABAergic choices still need indication, dose limits, and monitoring — they are not automatic free passes.[13][22][17]

Class comparison for viva: mechanism, dependence risk, and elderly harm before brand preference.[1][7][13]

Dependence risk, taper, and deprescribing

Physiological dependence (tolerance + withdrawal) can occur with therapeutic doses after continuous use; sedative/hypnotic/anxiolytic use disorder is the full behavioural syndrome (covered in depth in the benzodiazepine-dependence topic). High-potency short-acting agents, higher doses, longer duration, prior substance use disorder, and multiple prescribers raise risk.[1][3][2]

Taper principles (must-know):

1. Confirm actual dose (prescribed vs taken), agent, duration, co-use of alcohol/opioids/gabapentinoids.
2. Prefer gradual dose reduction; convert short-acting high-potency agents to a longer agent (often diazepam equivalents) when interdose withdrawal or complex polypharmacy confounds the taper.
3. Common teaching scaffold: reduce by about 10–25% of the daily dose every 1–2 weeks (sometimes slower), with smaller steps in the final phase; symptom-triggered pauses beat macho schedules.
4. If seizures or severe withdrawal emerge: reinstate adequate GABA cover, then restart a slower taper — medical emergency pathway as needed.
5. Treat the underlying anxiety/insomnia with SSRI/SNRI, CBT/CBT-I, and sleep hygiene rather than endless GABA substitution.[1][3][4][12]

Meta-analysis supports structured discontinuation strategies over abrupt advice alone.[4] Psychosocial interventions help harmful use/dependence pathways; pharmacological adjuncts for discontinuation have mixed Cochrane support — do not invent a miracle taper pill.[10][11] EMPOWER showed direct patient education can reduce inappropriate long-term benzodiazepine use in older adults; Canadian BRZA deprescribing guidance operationalises shared decision and tapering in primary care-style settings.[8][9]

Elderly patients — falls, cognition, Beers

In older adults, benzodiazepines and Z-drugs associate with falls, fractures, cognitive impairment, delirium risk, and motor vehicle accidents. Glass meta-analysis quantified unfavourable risk–benefit for sedative-hypnotics in older people with insomnia; Markota reviews clinical dangers and alternatives; AGS Beers Criteria continue to list these agents as potentially inappropriate medications in older adults.[7][6][27] Prefer non-drug sleep strategies, treat depression/pain/nocturia causes of insomnia, and if medicine is unavoidable use the lowest dose for the shortest time with falls precautions — melatonin is a modest option, not a miracle.[23][16]

Interactions and overdose

Critical combinations: opioids + benzodiazepines (overdose association in large data); alcohol + any sedative-hypnotic; stacked CNS depressants (antipsychotics, gabapentinoids, sedating antidepressants).[25][2][5]

Overdose management principles: airway and ventilation first; supportive care; flumazenil only in highly selected pure iatrogenic settings — can precipitate seizures in chronic users or mixed overdoses and is not a routine antidote. Naloxone for suspected opioid co-ingestion does not reverse benzodiazepine effects.[1][28]

Monitoring and shared decision

Before first GABAergic prescription: substance history; alcohol/opioid status; falls and driving risk; occupation (machinery); pregnancy potential; cognitive baseline; prior withdrawal seizures; pharmacy reconciliation; capacity and goals; written duration and exit plan.[2][5]

Early review: efficacy, sedation, falls, confusion, complex sleep behaviours (Z-drugs), dose escalation, multiple prescribers. If still needed beyond a short course, re-diagnose the maintaining problem rather than renew by default.[15][28]

These anchors compress Glass, Sun, EMPOWER, and taper teaching into viva-ready fragments.[7][25][8][1][22]

Special populations

Pregnancy/lactation. Avoid routine benzodiazepines; if used near term, anticipate neonatal floppy infant and withdrawal syndromes — individualised risk–benefit with obstetric liaison. Prefer non-drug anxiety/insomnia care and pregnancy-compatible antidepressants when indicated for underlying disorders.[13]

Youth. Avoid chronic benzodiazepines for anxiety; first-line psychological therapies and SSRI pathways per anxiety guidance.[13][14]

Hepatic disease. LOT agents; avoid long-acting oxidative metabolites when possible.[2]

Renal impairment. Adjust pregabalin; sedation risk rises with accumulation of many CNS drugs.[17]

Dementia/delirium. Benzodiazepines often worsen confusion and falls — not first-line behavioural management (see delirium and BPSD topics).[6][27]

Regional guideline deltas

Complications and exam pitfalls

Prognosis and disposition

Most patients given a true short course and an exit plan avoid long-term dependence. Once continuous use is established, success rates improve with structured taper plus psychosocial support and treatment of primary anxiety/insomnia; high-dose use, seizure history, or unstable polysubstance use may need specialist addiction/inpatient pathways (see benzodiazepine-dependence topic).[1][4][10]

Exam pearls

• Short-term only for BZD/Z-drugs in primary anxiety/insomnia unless specialist exception.[13][15]
• Half-life dictates withdrawal tempo; alprazolam is a high-potency short-acting trap.[1][3]
• LOT in liver disease.[2]
• Z-drugs remain dependence-capable and Beers-listed in older adults.[28][27]
• Buspirone: delayed; no GABA withdrawal cover.[22]
• Pregabalin: GAD RCTs real; renal dose; misuse vigilance.[17][19]
• Opioid + BZD = overdose synergy.[25]
• Flumazenil is not default antidote in chronic users.[1]
• EMPOWER + Canadian BRZA = deprescribing evidence language.[8][9]

Related topics

Cross-link benzodiazepine dependence for deep use-disorder and detox detail; GAD and panic topics for durable SSRI/SNRI/CBT pathways; alcohol and opioid topics for cross-tolerance and lethal combinations; agitation/rapid tranquillisation for acute parenteral pathways.[1][13][25]

References

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