Prescribing Lorazepam (Ativan)

Why Lorazepam Still Matters

Lorazepam is the workhorse benzodiazepine of general psychiatry and emergency medicine, and it earns that role by being the simplest member of a complicated class. It does one thing extremely well: it turns anxiety and agitation off within an hour, and it does it with a pharmacokinetic profile that is easier to reason about than almost any of its competitors: an intermediate half-life, no active metabolites, and metabolism by glucuronidation rather than the cytochrome P450 system. That last fact means lorazepam sidesteps the drug-interaction minefield that trips up alprazolam and diazepam, and it makes lorazepam the benzodiazepine of choice in exactly the patients who are most fragile: the elderly, the cirrhotic, the medically complex, the polypharmacy patient.

It is also one of the few psychiatric drugs that is genuinely safe in overdose. A benzodiazepine taken alone almost never kills. As Carl Salzman puts it, benzodiazepines are "among the safest drugs we have"; the fatal risk lives almost entirely in the combinations, above all with opioids and alcohol.

But safety in overdose is not the same as safety over time, and this is where lorazepam demands respect. It produces physiologic dependence within weeks. Its cognitive and motor toll (falls, car accidents, memory fog) is real, often invisible to both patient and prescriber, and disproportionately borne by older adults. And it can be genuinely hard to stop, with a withdrawal syndrome that ranges from rebound anxiety to, rarely, seizures, and a protracted tail that can outlast the taper by months.

Part 1: Indications: Who Is Lorazepam For?

FDA-Approved Uses

• Anxiety (short-term relief of anxiety symptoms and anxiety associated with depressive symptoms)
• Insomnia due to anxiety or transient situational stress (short-term)
• Status epilepticus and acute repetitive seizures (IV; first-line)
• Preanesthetic medication (sedation, anxiolysis, anterograde amnesia before procedures)
• Chemotherapy-induced nausea and vomiting (adjunct, often for anticipatory nausea)

Lorazepam injection for status epilepticus is FDA-approved only in adults (≥18); a pediatric efficacy trial failed and safety/effectiveness in children was not established, so pediatric use for status epilepticus—though guideline-supported—is off-label. Oral lorazepam is FDA-approved for anxiety only down to age 12.

Where Lorazepam Genuinely Earns Its Place

Acute anxiety and panic: the core outpatient role. Fast, reliable relief within ~1 hour orally. Benzodiazepines carry a medium effect size for anxiety (~0.5) versus the small effect size of SSRIs (~0.3), work far faster, and also help sleep. They are not first-line for any chronic anxiety disorder (SSRIs/SNRIs plus CBT are), but for bridging the weeks until an antidepressant works, for breaking a panic spiral, or for a discrete high-anxiety event, lorazepam is excellent.

Situational and time-limited insomnia. Insomnia triggered by a bounded stressor (a death, a move, a new job, a hospitalization) is a legitimate short-course indication.

Status epilepticus: standard of care. IV lorazepam is a first-line agent for terminating status epilepticus; its relatively longer CNS duration versus IV diazepam is an advantage here.

Alcohol withdrawal. Lorazepam is a standard agent for managing and preventing alcohol-withdrawal syndrome, and it is the preferred benzodiazepine in withdrawal patients who also have significant liver disease, precisely because it does not depend on hepatic oxidation and does not accumulate.

Acute agitation. IM/IV lorazepam is a mainstay of acute agitation management, alone or combined with an antipsychotic. Prompt control of agitation "can be potentially life-saving in a crisis."

Catatonia. The lorazepam challenge test (typically 1–2 mg IV or IM, repeated) is both diagnostic and therapeutic; a response supports the diagnosis and often the ongoing treatment.

Adjuncts in inpatient psychiatry. Short-term add-on to control agitation in acute mania (e.g., 1–2 mg q8–12h), to blunt akathisia, and to manage antipsychotic- or mood-stabilizer-associated nausea.

Chemotherapy-related and anticipatory nausea. A useful adjunct, particularly for the anticipatory, anxiety-driven component.

Where Lorazepam Is the Wrong Tool

• Chronic daily anxiety as a long-term monotherapy: tolerance to the anxiolytic effect is variable and the cumulative cognitive/fall burden grows.
• Chronic insomnia: hypnotic tolerance develops fast (weeks), and it distorts sleep architecture.
• OCD: no efficacy for core symptoms.
• PTSD: scant evidence; may interfere with exposure-based recovery and worsen long-term outcomes.
• Active opioid use disorder or active substance use: see Contraindications; this is where the drug kills.
• Borderline or antisocial personality disorder: risk of paradoxical disinhibition and impulsive self-harm.

Part 2: Before You Start: Candidacy and Workup

Lorazepam requires no baseline labs, no serum-level monitoring, and no ECG (it does not prolong QT). The "workup" is a risk assessment, not a blood draw.

The pre-prescribing checklist

• Substance use history. Ask specifically and directly about opioids (prescribed and illicit), alcohol, and prior sedative misuse. This is the single most important screen.
• Current medications. Above all, opioids and other CNS depressants (muscle relaxants, sedating antipsychotics, gabapentinoids, z-drugs). Check the state prescription-monitoring database (PDMP).
• Respiratory status. COPD and untreated obstructive sleep apnea raise the risk of respiratory depression.
• Age and fall risk. Age ≥65, prior falls, gait/balance problems, cognitive concerns.
• Personality and behavioral history. BPD/ASPD and any history of disinhibited violence.
• Pregnancy status / plans in patients of childbearing potential.
• Hepatic status: relevant to agent choice, but lorazepam is the safe answer here rather than a contraindication.

Who is a poor candidate?

• Active opioid use disorder (contraindication)
• Active alcohol or other sedative/substance use disorder
• Untreated severe sleep apnea or advanced COPD
• Borderline/antisocial personality disorder with disinhibition history (relative)
• Patients who cannot be relied on for a time-limited, planned course

Set the frame on day one

Before the first tablet, say three things out loud and document them:

1. This is for short-term / specific use, and we have a plan for how it ends.
2. Never combine it with alcohol or opioids; do not drive at peak effect (30–60 minutes after a dose).
3. If you take it steadily, your body adapts (physiologic dependence), so we never stop it abruptly; we taper.

Part 3: How to Start and Dose

Formulations

• Immediate-release tablets: 0.5, 1, 2 mg.
• Oral concentrate/liquid (2 mg/mL): invaluable for precise tapering and for sublingual/small-dose adjustments.
• Sublingual administration (tablets used sublingually): somewhat faster onset than swallowed.
• Injectable (IM/IV): the emergency workhorse: status epilepticus, agitation, catatonia, alcohol withdrawal, preanesthesia.
• Loreev XR (extended-release capsules, 1/2/3 mg): once-daily (QAM), can be opened and sprinkled on food, no food interaction, peaks at ~14 hours. FDA approval rests on pharmacokinetics rather than clinical outcome trials; the theoretical draw is steadier levels and lower abuse liability, at ~$300/month.

Onset, duration, and the half-life paradox

This trips up prescribers, so internalize it:

• Onset (oral IR): ~30–60 minutes to meaningful effect; peak serum ~1–2 hours. Sublingual is faster; IM/IV onsets in minutes.
• Half-life: ~10–12 hours (intermediate).
• Clinical duration of a single dose: only ~4–6 hours, shorter than the half-life would predict, because lorazepam redistributes out of the brain into fat.

The consequence: a drug with a modest half-life that nonetheless feels short-acting to patients, which is why standing anxiety coverage often requires 2–3 doses a day while the half-life is long enough to avoid the sharp inter-dose withdrawal peaks of ultra-short agents like alprazolam. That combination (fast on, moderately fast off, but no wild swings) is much of why lorazepam is so clinically manageable.

Starting doses by indication

General principle: start low, titrate slowly (every few days), use the lowest dose that restores function, not the dose that abolishes all anxiety.

Standing versus PRN: a decision that matters

• Standing (scheduled) dosing carries lower misuse/escalation risk than PRN, gives steadier relief, and is preferred for severe or continuous anxiety and when a patient is doing CBT (breakthrough anxiety defeats exposure work).
• PRN dosing is right for genuinely intermittent, situational needs (flying, a dental procedure, a known trigger) in conscientious patients.
• The 50% rule: if a patient is using their PRN more than ~50% of days, that is a signal to convert to a scheduled dose or to reassess the whole plan: it usually means escalating need, not a lucky dosing schedule.
• Do not tell tapering patients to "skip doses": that produces blood-level swings and withdrawal, especially with shorter-acting agents.

Dosing tips patients get wrong

• Do not drive at peak (30–60 minutes post-dose). Reaction time is most impaired then, and remains somewhat impaired even on steady chronic dosing. Patients are typically unaware of their own impairment.
• Food delays onset (and antacids do too); take on an empty stomach when speed matters.
• Get into bed immediately after a bedtime dose to avoid sleep-walking/-eating/-driving behaviors.

Part 4: Monitoring

There is no therapeutic drug level to chase and no required labs. Monitoring is clinical and behavioral.

Watch specifically for:

• Dose creep / early refills: the earliest sign of tolerance or misuse.
• Cognitive impairment: insidious and often invisible. Ask the patient and a family member.
• Falls in older adults (highest risk in the first ~2 weeks).
• Sedation and morning drowsiness: in elderly, morning grogginess ("takes me three hours to get dressed," "I go right back to bed after breakfast") is a red flag for occult toxicity.
• Emergent depression: long-term use can deepen depression; it often lifts after a successful taper.
• Suicidality during tapering (withdrawal akathisia is a specific, dangerous driver).

Part 5: Side Effects and How to Manage Them

The governing principle: most acute side effects (sedation, unsteadiness) are mild and remit within days as tolerance develops; the effects that matter over time (cognitive dulling, falls, dependence) are the ones patients and prescribers underestimate.

Sedation and psychomotor slowing

Common early, usually mild, and typically resolves within a few days as tolerance to sedation develops (note: tolerance develops to sedation, usually not to the anxiolytic effect: reassure patients the drowsiness fades but the anxiety relief should persist).

Management: lower the dose; shift more of the dose to bedtime; give the daytime dose after the workday if feasible; reassess if it persists.

Motor impairment, falls, and driving

• Falls: roughly a 1.5-fold increase, concentrated in the first ~2 weeks and in the elderly.
• Motor vehicle accidents: on the order of a 60–80% increase (some data suggest a 2–4 fold, dose-dependent risk), driven by impaired processing speed and attention: impairment the driver usually can't feel.

Management: use the lowest effective dose; counsel explicitly against driving at peak (30–60 min); in older adults weigh whether a benzodiazepine belongs at all (Beers criteria advise against benzodiazepines in older adults for most indications). Switching to a z-drug does not reliably reduce fall risk.

Cognitive impairment

Real, often subtle, and frequently missed. Affects memory formation, processing speed, and attention, with moderate-to-large effect sizes in chronic use. Partially reversible after discontinuation, though some deficits can persist for up to a year.

Management: keep courses short; use the lowest dose; enlist family observation; when in doubt, taper to unmask it. A distinct anterograde amnesia effect (part of why lorazepam is used preoperatively) is expected acutely.

Respiratory depression

Modest with lorazepam alone; dangerous in combination with opioids or alcohol, and a real concern in COPD and untreated OSA.

Management: avoid the dangerous combinations (see Interactions and Contraindications); use cautiously or not at all in significant respiratory disease.

Dependence and withdrawal

Physiologic dependence develops with regular therapeutic dosing over ~3–6 weeks. This is expected pharmacology, not addiction, but it means abrupt cessation risks withdrawal (covered in full in Part 9).

Paradoxical reactions / disinhibition

Uncommon but documented: agitation, aggression, impulsivity, self-harm. Higher risk in BPD/ASPD, developmental disability, dementia, and the elderly.

Management: stop the drug; document; avoid re-challenge; avoid benzodiazepines in the high-risk groups above.

Depression

Long-term use can precipitate or deepen depressive symptoms; these often improve within months of a successful taper.

Nausea (when lorazepam is the treatment)

For lithium/mood-stabilizer or chemotherapy nausea, options include ondansetron 4 mg PRN, ginger 1,000–2,000 mg q12h PRN, lorazepam 0.5–1 mg q8h PRN, or olanzapine 5 mg q12h PRN.

Part 6: Overdose, Toxicity, and Boxed Warnings

The reassuring headline

Lorazepam alone is almost never fatal in overdose. Deep sedation, ataxia, dysarthria, and confusion occur, but respiratory drive is largely preserved, unlike the barbiturates it replaced. Among benzodiazepines, lorazepam sits near the bottom of the toxicity-index ranking (oxazepam lowest, then lorazepam; alprazolam is the most toxic).

The lethal exception

The danger is combination. Benzodiazepines suppress breathing via GABA-A; opioids suppress the medullary respiratory center; alcohol adds its own depression. Stacked, the effect is synergistic and can be fatal. In 2018, benzodiazepines were detected in roughly half of opioid overdose deaths, a roughly four-fold rise over the prior two decades. Co-prescription with opioids raises overdose risk 2–4 fold, and the risk climbs with benzodiazepine dose (it does not differ meaningfully between daily and PRN dosing).

Overdose management

• Supportive care is the mainstay: airway, breathing, circulation; monitor for aspiration and respiratory depression.
• Naloxone for suspected combined benzodiazepine-opioid overdose (reverses the opioid component and the respiratory depression it drives); consider naloxone co-prescription for any patient on both classes.
• Flumazenil (the benzodiazepine antagonist) reverses effects in monitored settings but is not routinely recommended and not for home use: it can precipitate seizures and withdrawal, especially in chronic users or mixed overdoses (e.g., with a TCA).

Part 7: Drug Interactions

Here lorazepam's chemistry is a gift.

The big advantage: no CYP450 metabolism

Lorazepam is cleared by glucuronidation (phase II, UGT), not the cytochrome P450 system, and it has no active metabolites. The practical payoffs:

• No meaningful interaction with CYP inhibitors that plague other benzodiazepines: fluoxetine, fluvoxamine, oral contraceptives, and other CYP3A4/2C19 inhibitors raise alprazolam and diazepam levels but leave lorazepam essentially alone.
• No interaction with CYP inducers (e.g., carbamazepine) in the way that lowers other benzo levels.
• Predictable, linear kinetics, part of why it's preferred in polypharmacy.

The interactions that DO matter

CNS depressants: the dangerous axis

• Opioids: the marquee risk: synergistic respiratory depression, potentially fatal, boxed warning (see Part 6). Longer-acting/XR benzos plus opioids carry the greatest overdose risk.
• Alcohol: additive/synergistic CNS depression, fatal at high combined levels, and a major driver of accidents at moderate levels. Counsel every patient; for most people more than one drink a day is too much on a benzo, and for the elderly or medically ill, any alcohol is too much.
• Other sedatives: muscle relaxants (baclofen, cyclobenzaprine), sedating antipsychotics, gabapentinoids, z-drugs, and barbiturates all stack additively.

Valproate: the one pharmacokinetic interaction worth knowing. Valproate inhibits glucuronidation and can roughly double lorazepam levels, increasing sedation. When co-prescribing, use a lower lorazepam dose and watch for excess CNS depression.

CBD can inhibit UGT2B7 and modestly raise lorazepam levels, worth knowing in patients using cannabis products.

Disulfiram reduces benzodiazepine clearance and can raise levels.

What lorazepam does NOT meaningfully interact with

• Fluoxetine, fluvoxamine, and other CYP inhibitors (unlike alprazolam).
• Oral contraceptives.
• MAOIs: the combination is considered safe, which makes lorazepam a useful bridging anxiolytic during antidepressant washouts.

Part 8: Special Populations

Elderly (≥65)

This is where lorazepam's profile shines and where benzodiazepines are most hazardous, both at once.

• Why lorazepam over other benzos here: glucuronidation (no hepatic-oxidation interactions), no active metabolites, and it does not accumulate the way diazepam and clonazepam do. If a benzodiazepine must be used in an older adult, lorazepam or oxazepam is the answer.
• But the class risks are amplified: ~50% higher fall risk, 60–80% higher MVA risk, delirium, and cognitive impairment, all worse with age-related CNS sensitivity and slowed clearance. Beers criteria advise avoiding benzodiazepines in older adults for most indications.
• Practical approach: start very low (e.g., 0.25–0.5 mg), space intervals, keep courses short, watch the first two weeks for falls, and periodically consider a taper to unmask hidden toxicity.
• Dementia risk: the older observational signal (1.5–1.8 fold increased AD risk) is confounded by indication; recent controlled prospective studies show minimal-to-no association. Cognitive and fall risks alone justify caution: don't overweight the dementia question either way.

Pregnancy

• Benzodiazepines cross the placenta. First-trimester exposure was historically linked to oral cleft risk; more recent data have weakened that association, though it is still taken seriously.
• If a benzodiazepine is genuinely necessary, lorazepam is preferred: shorter half-life, no active metabolites, less fetal accumulation than diazepam.
• Late-pregnancy exposure risks neonatal sedation ("floppy infant") and withdrawal.
• Approach: favor non-pharmacologic care (CBT, therapy); use the lowest dose, intermittently, ideally after the first trimester if unavoidable; individualize against the risk of untreated maternal illness.

Lactation

• Lorazepam is regarded as the safest benzodiazepine in breastfeeding: low milk transfer, short half-life, no active metabolites.
• Preferred over diazepam (long half-life, infant accumulation and lethargy).
• If used chronically, monitor the infant for sedation and poor feeding.
• Useful in the postpartum period for sedation/sleep support (e.g., alongside lithium or an antipsychotic in postpartum mania/psychosis prophylaxis).

Hepatic impairment

• Lorazepam is the benzodiazepine of choice in liver disease. Because it's glucuronidated rather than oxidized, it shows minimal accumulation even in cirrhosis, with no active metabolites.
• Avoid diazepam, alprazolam, and clonazepam (hepatic oxidation, accumulation).

Renal impairment

Lorazepam itself is less affected than benzodiazepines whose active metabolites depend on renal clearance; the inactive glucuronide is renally excreted, so use standard caution and lower doses in significant renal impairment, but lorazepam remains a reasonable choice.

Pediatrics

Oral lorazepam is FDA-approved for anxiety down to age 12. Use in status epilepticus/seizures in younger children is guideline-supported but off-label (the pediatric efficacy trial failed to establish efficacy, and safety was not established). Use is specialist-guided; dose by weight and indication.

Substance use history

• Active opioid use disorder: contraindicated: benzodiazepines enhance the opioid high and can restart an abuse cycle, on top of the overdose risk.
• Active alcohol/other substance use: avoid outside supervised withdrawal management.
• Remote alcohol use disorder in stable recovery: cautious use is acceptable with monitoring and recovery support (see Part 2).
• Misuse risk is strongly age-dependent (much higher in young adults than in those ≥65) and occurs overwhelmingly in the context of other substance use; pure benzodiazepine addiction in a therapeutic population is uncommon.

Part 9: Discontinuation and Withdrawal (Handle With Care)

Stopping lorazepam badly is the most common way a well-intended prescription turns into harm.

The principle

After ~4 weeks of regular use, plan for eventual deprescribing in most patients, unless there is a clear reason to continue (a specific seizure disorder, end-of-life care, or severe illness where tapering would destabilize). Physiologic dependence is expected pharmacology, not moral failure or proof the drug is "needed"; frame it that way to the patient.

The taper

• Timeline: roughly 5–6 weeks for lower doses; months to a year or more for higher-dose, long-term users.
• Rate: a workable frame is ~25% every 2 weeks early, slowing to ~12.5% (or less) near the end. Alternatively, reduce ~5% every 2 weeks and slow further as the dose drops. The universal rule: the last portion of the taper is the hardest, go slowest at the bottom.
• Hyperbolic tapering (reduce a fixed percentage of the current dose each step, yielding smaller and smaller absolute cuts) is the preferred model for the tail end.
• Use the liquid concentrate for the sub-milligram reductions the tablets can't achieve; grinding-and-dissolving or compounded tapering strips are alternatives.
• Do not dose-skip to taper: consistent daily reduction avoids the blood-level swings that trigger withdrawal, which matters more for a shorter-acting agent like lorazepam.
• Don't reflexively switch to diazepam for the taper; the older cross-taper strategy carries accumulation risk (especially in the elderly), and current practice generally favors tapering the agent the patient is already on.
• Monitor every 1–2 weeks, and flexibly slow (or pause) the taper for the patient's tolerance: success depends far more on therapeutic alliance than on any fixed schedule.

Post-acute withdrawal syndrome (PAWS)

A minority develop protracted symptoms (anxiety, cognitive fog, paresthesias, tinnitus, mood lability) persisting weeks to months (occasionally longer) beyond the ~4–6 week acute phase. Recognize it so it isn't misread as relapse or a new diagnosis. Prevention (slow taper) beats rescue.

Adjuncts and support (evidence is limited)

• No medication reliably treats benzodiazepine withdrawal. Modest-evidence adjuncts: propranolol 60–120 mg/day, pregabalin 200–400 mg/night, gabapentin, carbamazepine 200–800 mg/day.
• CBT for insomnia (CBT-I) is as effective as a benzodiazepine for sleep and is strongly recommended alongside the taper.
• Sleep hygiene, relaxation/mindfulness, gentle exercise, and psychotherapy carry the load. Useful apps: SleepioRx, Somryst, Sleep Coach (insomnia); Calm, Headspace, Breathe2Relax, DayLightRx (anxiety).

A caution on the risk-benefit of stopping

A large 2023 analysis (Maust et al.) found increased mortality when benzodiazepines were withdrawn even in high-risk groups (elderly, opioid co-users). The lesson is not "never taper"; it's that untreated anxiety and abrupt/coercive discontinuation carry their own risks. Deprescribe deliberately, collaboratively, and slowly; if a taper repeatedly fails and symptoms are intolerable, maintaining the lowest effective dose is a legitimate harm-reduction position.

Part 10: Lorazepam vs the Alternatives

Within the benzodiazepine class

Onset/duration hierarchy (roughly): alprazolam (fast on, short) → lorazepam (fast-ish on, intermediate) → clonazepam (slower, long) → diazepam (fast on, long, accumulates).

vs Alprazolam: Alprazolam is faster and punchier (better for acute PRN panic) but has a higher toxicity index, higher abuse potential, and sharper inter-dose withdrawal. Lorazepam is smoother, safer in overdose, and cleaner on interactions. For most maintenance-ish or elderly use, lorazepam wins.

vs Clonazepam: Clonazepam's long half-life gives once/twice-daily coverage and a gentler withdrawal curve, but it accumulates and raises fall risk in the elderly. Lorazepam is preferred for acute use and in older/medically ill patients.

vs Diazepam: Diazepam accumulates (active metabolites, high lipophilicity, 50+ hour effective half-life in the elderly) and depends on hepatic oxidation. Lorazepam avoids all of that (no hepatic interactions, no active metabolites), making it far safer in the elderly and the hepatically impaired.

The "LOT" drugs (Lorazepam, Oxazepam, Temazepam): all glucuronidated, no active metabolites, no CYP interactions: the gold standard for the elderly and liver disease. Oxazepam edges lorazepam on the lowest toxicity/abuse index but has a slow ~3-hour onset that makes it clumsy for acute use.

Versus non-benzodiazepines

vs SSRIs/SNRIs: Benzos work faster and carry a larger effect size for GAD (~0.5 vs ~0.3), and they help sleep, but SSRIs/SNRIs are first-line for chronic anxiety because they lack dependence and cognitive/fall burden. The classic play is a short lorazepam bridge while the antidepressant ramps up.

vs z-drugs (zolpidem, eszopiclone): z-drugs act mainly at the alpha-1 subunit (sedation), so they're narrower (little anxiolysis); they do not reliably reduce fall risk versus benzos and are not clearly safer in the elderly, though they are preferred over benzos in sleep apnea/COPD for respiratory safety.

vs buspirone: Buspirone is non-sedating and non-dependence-forming but slow in onset and generally less potent: an option for chronic GAD, useless for acute distress.

vs propranolol: Excellent for the physiologic symptoms of anxiety (tremor, palpitations, performance anxiety), non-sedating, no cognitive impairment, no dependence, but it doesn't touch the psychic dread the way a benzo does.

So when is lorazepam the right benzo? Acute anxiety/panic relief; short-term/situational insomnia; the elderly and medically/hepatically ill (LOT advantage); patients on strong CYP inhibitors; alcohol withdrawal with liver disease; status epilepticus; catatonia; acute agitation; and any time you want fast, clean, low-interaction, low-overdose-toxicity anxiolysis for a bounded period.

Mechanism: The Short Version

Lorazepam is a positive allosteric modulator of the GABA-A receptor. It binds the benzodiazepine site on the receptor complex and "turbocharges" the effect of the brain's own GABA, increasing the frequency of chloride-channel opening, hyperpolarizing neurons, and dialing down neuronal firing. It does not open the channel on its own; it amplifies native GABA, which is part of why benzodiazepines are comparatively safe in overdose (there's a ceiling set by available GABA).

Benzodiazepines act at receptors carrying both the alpha-1 subunit (sedation/hypnosis) and the alpha-2 subunit (anxiolysis), which is why they both calm anxiety and induce sleep, unlike the z-drugs, which are alpha-1-selective and therefore mostly hypnotic. Chronic exposure drives receptor adaptation (and suppression of endogenous benzodiazepine-like "endozepine" tone), which the brain must re-establish during a taper: the neurobiology behind physiologic dependence and withdrawal.

Pharmacokinetically, lorazepam's defining features are glucuronidation (no CYP450, no active metabolites) and a ~10–12 hour half-life paired with fat-redistribution that shortens its clinical duration to ~4–6 hours: the profile that makes it both predictable and manageable.

The Bedside Cheat Sheet