Lorazepam
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Anxiety disorders / short-term relief of anxiety symptoms | Adults (≥12 years for oral) | Monotherapy | FDA Approved |
| Anxiety-related insomnia | Adults | Monotherapy (short-term) | FDA Approved |
| Status epilepticus | Adults ≥18 years (IV) | First-line emergency treatment | FDA Approved |
| Anesthesia premedication | Adults (IV/IM) | Adjunctive | FDA Approved |
Lorazepam is a 3-hydroxy benzodiazepine widely used across psychiatry, emergency medicine, anesthesiology, and critical care. Its key pharmacokinetic advantage over many other benzodiazepines is metabolism via direct glucuronidation rather than CYP450 oxidation, making it a preferred choice in patients with hepatic dysfunction or those on multiple medications. For anxiety, the FDA has not established efficacy beyond 4 months of continuous use. Lorazepam IV is considered first-line for convulsive status epilepticus by both the American Epilepsy Society and Neurocritical Care Society guidelines.
Alcohol withdrawal syndrome: Widely used as first-line; symptom-triggered dosing guided by CIWA-Ar scale. Evidence quality: High.
Chemotherapy-induced anticipatory nausea/vomiting: Adjunctive or breakthrough treatment. Evidence quality: Moderate.
Acute agitation / rapid tranquilisation: IM lorazepam alone or with haloperidol. Evidence quality: High (hospital practice).
Psychogenic catatonia: Lorazepam challenge (1–2 mg IV) is both diagnostic and therapeutic. Evidence quality: Moderate.
Panic disorder: Used off-label when first-line SSRIs/SNRIs are insufficient. Evidence quality: Moderate.
Dosing
Oral — Anxiety and Insomnia
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Generalised anxiety — mild to moderate | 1 mg BID–TID | 2–3 mg/day divided | 6 mg/day | Titrate gradually; reassess after 4 months Largest dose before bedtime (FDA PI) |
| Generalised anxiety — moderate to severe | 1 mg TID | 2–6 mg/day divided | 10 mg/day | Usual effective range 2–6 mg/day Full daily range: 1–10 mg/day (FDA PI) |
| Anxiety-related insomnia | 2 mg at bedtime | 2–4 mg at bedtime | 4 mg at bedtime | Single nightly dose; short-term use only Not for chronic primary insomnia |
| Elderly or debilitated patients | 1–2 mg/day divided | Titrate as needed and tolerated | Lowest effective | Increased sensitivity to sedation and unsteadiness Initial dose should not exceed 2 mg total (FDA PI) |
| Conversion to Loreev XR | Total daily IR dose, once daily AM | Equal to total daily IR dose | Per IR total daily dose | Only for patients stable on TID immediate-release dosing; capsules available as 1, 2, 3 mg Swallow whole or sprinkle on applesauce; for dose adjustment, switch back to IR tablets |
Parenteral — Status Epilepticus and Procedural
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Status epilepticus (adults ≥18) | 4 mg IV at 2 mg/min | Repeat 4 mg after 10–15 min if seizures persist | 8 mg total | First-line per AES guidelines (0.1 mg/kg, max 4 mg/dose) Have airway equipment immediately available |
| Premedication — IV sedation | 2 mg IV total (or 0.044 mg/kg) | N/A (single dose) | 4 mg | Give 15–20 min before procedure for amnesia Reduce dose in patients >50 years |
| Premedication — IM | 0.05 mg/kg IM | N/A (single dose) | 4 mg | Give at least 2 hours before procedure for optimal effect IM absorption is rapid and complete |
| Alcohol withdrawal (off-label) — symptom-triggered | 1–4 mg IV/IM q1h PRN | CIWA-Ar guided: dose when score ≥8–10 | Clinician discretion | Preferred over diazepam in hepatic impairment Taper as symptoms resolve |
| Acute agitation (off-label) | 1–2 mg IM | Repeat q30–60 min PRN | Clinician discretion | Often combined with haloperidol 5 mg IM Monitor for respiratory depression |
Unlike diazepam, alprazolam, and midazolam, lorazepam bypasses the CYP450 system entirely. Its metabolism occurs exclusively through direct glucuronidation (UGT), which is relatively preserved in liver disease. The FDA PI notes that the half-life of lorazepam is not significantly altered by hepatic dysfunction. This makes lorazepam the preferred benzodiazepine for patients with cirrhosis, alcoholic liver disease, or those on CYP450-inhibiting medications. However, caution is still warranted in severe hepatic insufficiency, as glucuronidation capacity can eventually become impaired, and lorazepam may worsen hepatic encephalopathy.
Pharmacology
Mechanism of Action
Lorazepam is a 3-hydroxy benzodiazepine that exerts its effects through binding to the benzodiazepine site on the GABA-A receptor complex. By allosterically enhancing GABA-mediated chloride conductance, lorazepam increases the frequency of chloride channel opening, producing neuronal hyperpolarisation and membrane stabilisation. This translates into anxiolytic, sedative, anticonvulsant, muscle-relaxant, and amnestic effects. Compared to diazepam, lorazepam has lower lipid solubility, which limits its initial redistribution from the brain after a single dose and accounts for its longer duration of anticonvulsant action (over 12 hours vs approximately 20–30 minutes for diazepam). This property makes lorazepam the preferred benzodiazepine for sustained seizure control in status epilepticus despite a slightly slower onset than diazepam.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Bioavailability ~90% (oral and IM); Tmax ~2 h (oral); onset 1–3 min (IV), 15–30 min (IM) | Oral onset slower than IV; IM absorption is rapid and complete, unlike diazepam IM which is erratic |
| Distribution | Vd 1.0–1.3 L/kg; ~85% protein bound (albumin); crosses placenta and blood-brain barrier | Low lipid solubility limits redistribution, prolonging CNS duration of action; enters breast milk |
| Metabolism | Direct hepatic glucuronidation to lorazepam glucuronide (inactive); no CYP450 involvement; no active metabolites | Minimal hepatic drug interaction potential; safe in liver disease (glucuronidation preserved); no accumulation on repeated dosing |
| Elimination | t½ ~12 h (range 8–25 h); clearance 0.7–1.2 mL/min/kg; 88% urine, 7% faeces; <0.5% excreted as unchanged drug | Age minimally affects kinetics; clearance modestly reduced (~20%) in elderly via IV route; glucuronide metabolite may be dialysable |
Side Effects
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Sedation | 15.9% | Most frequent effect; dose-dependent; incidence increases with age; typically attenuates over days to weeks |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Dizziness | 6.9% | May contribute to falls in elderly; assess at each visit |
| Weakness | 4.2% | Generalised muscle relaxation effect; asthenia reported alongside |
| Unsteadiness | 3.4% | Incidence increases with age; significant fall risk in elderly |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Amnesia / Memory Impairment | Frequent | Anterograde amnesia; dose-dependent; exploited therapeutically for procedural sedation but problematic for daily functioning |
| Drowsiness / Fatigue | Frequent | Overlaps with sedation; may impair driving and occupational performance |
| Depression / Unmasking of Depression | Reported | Pre-existing depression may worsen; not recommended as monotherapy in depressive disorders |
| Confusion / Disorientation | Reported | More common in elderly; may mimic delirium |
| Ataxia | Reported | Dose-related; contributes to fall risk along with unsteadiness |
| Dysarthria / Slurred Speech | Reported | Dose-dependent; particularly notable at higher doses |
| Hypotension | Reported | Small decreases in blood pressure; usually not clinically significant; more relevant with IV administration |
| Change in Libido / Impotence | Reported | Both increased and decreased libido reported; enquire actively |
| Nausea / GI Symptoms | Reported | Includes constipation and appetite changes |
| Visual Disturbance | Reported | Diplopia, blurred vision; dose-related |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Physical Dependence / Withdrawal Seizures | Common with prolonged use | On discontinuation; reported after as little as 1 week | Never stop abruptly; gradual taper essential; seizures can be life-threatening |
| Respiratory Depression / Apnoea | Dose-dependent; higher with IV route | Minutes after IV dose; hours after oral | Discontinue; ventilatory support; flumazenil as adjunct (caution: may precipitate seizures) |
| Paradoxical Reactions (rage, agitation, aggression) | Rare | Any time; more likely in elderly and children | Discontinue lorazepam immediately |
| Suicidal Ideation / Attempt | Uncommon | Any time; risk elevated with comorbid depression | Limit prescription quantity; ensure concurrent antidepressant therapy; psychiatric evaluation |
| Anaphylactoid Reactions / Angioedema | Very rare | First or subsequent doses | Discontinue permanently; emergency airway management if tongue/glottis involved; do not rechallenge |
| SIADH / Hyponatraemia | Very rare | Variable | Check serum sodium; fluid restrict; discontinue if severe |
| Blood Dyscrasias (agranulocytosis, pancytopenia, thrombocytopenia) | Very rare | Variable; monitor on long-term therapy | Periodic CBC recommended; discontinue if significant cytopenias develop |
| Neonatal Sedation / Withdrawal | Expected with late-pregnancy exposure | Birth / neonatal period | Monitor neonate for respiratory depression, hypotonia, feeding difficulties, withdrawal signs |
Sedation and unsteadiness incidence increases with age. The AGS Beers Criteria lists benzodiazepines as potentially inappropriate in older adults due to fall risk and cognitive impairment. If lorazepam must be used, start at the lowest dose (0.5 mg) and limit duration. Carefully evaluate the risk-benefit at every encounter, particularly in patients on other CNS-depressant medications.
Drug Interactions
Lorazepam is metabolised by direct glucuronidation (UGT) and does not involve CYP450 enzymes. This confers a significantly cleaner drug interaction profile compared to benzodiazepines such as alprazolam, diazepam, and midazolam. The clinically important interactions are pharmacodynamic (additive CNS depression) and involve UGT inhibitors that reduce glucuronidation clearance.
Unlike alprazolam (CYP3A4), diazepam (CYP2C19/3A4), and midazolam (CYP3A4), lorazepam is not affected by azole antifungals, macrolide antibiotics, HIV protease inhibitors, or grapefruit juice. This makes lorazepam the preferred benzodiazepine in patients on complex medication regimens, particularly those involving CYP3A4 or CYP2C19 inhibitors.
Monitoring
- Sedation & Psychomotor FunctionEach visit during titration; q3 months
RoutineAssess daytime sedation, driving safety, and occupational functioning. Elderly patients require particular attention. - Abuse / Misuse RiskBaseline, each visit
RoutineStandardised screening before prescribing. Monitor for dose escalation, early refill requests, multiple prescribers. - Mood & SuicidalityEach visit
RoutinePre-existing depression may emerge or worsen. Not recommended for primary depressive disorders without concurrent antidepressant therapy. - CBC & Liver FunctionBaseline; periodically on long-term therapy
RoutineLeukopenia and elevated LDH have been reported. Periodic blood counts and LFTs recommended for patients on prolonged therapy (FDA PI). - Respiratory FunctionBaseline; ongoing in COPD/sleep apnoea
Trigger-basedUse with caution in compromised respiratory function. Worsening of sleep apnoea and COPD reported. Continuous monitoring essential with IV administration. - Fall Risk (Elderly)Baseline, q3 months
RoutineUnsteadiness and ataxia are dose-dependent. Consider Timed Up and Go test. Deprescribing should be considered after any fall. - Upper GI SymptomsPeriodically on prolonged use
Trigger-basedEsophageal dilation observed in long-term rat studies. Monitor for symptoms of upper GI disease, particularly in elderly on prolonged therapy. - Treatment Duration Reviewq3 months
RoutineFDA has not established efficacy beyond 4 months. Document clinical justification for continued use. Consider tapering when anxiety is well-managed.
Contraindications & Cautions
Absolute Contraindications
- Known hypersensitivity to lorazepam, other benzodiazepines, or any formulation component
- Acute narrow-angle glaucoma
Relative Contraindications (Specialist Input Recommended)
- Primary depressive disorder or psychosis — not recommended without concurrent appropriate therapy; benzodiazepines may worsen depression
- Severe hepatic insufficiency with encephalopathy — may worsen hepatic encephalopathy despite preserved glucuronidation
- Severe respiratory disease — COPD, severe sleep apnoea; dose-dependent respiratory depression risk
- Active substance use disorder — high abuse potential; documented risk-benefit required
- Pregnancy (especially late trimester) — risk of neonatal sedation/withdrawal; avoid unless urgently needed
Use with Caution
- Elderly patients — increased sensitivity to sedation and unsteadiness; AGS Beers Criteria lists as potentially inappropriate
- Renal impairment — caution with frequent dosing; lorazepam glucuronide may accumulate
- Children <12 years — safety and effectiveness not established (oral); paradoxical reactions may be more likely
- Injection formulation — contains propylene glycol and benzyl alcohol; risk of toxicity with high cumulative IV doses (propylene glycol acidosis) and in neonates (gasping syndrome from benzyl alcohol)
Combined use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for patients with no adequate alternative. Use lowest effective doses for the shortest possible duration.
Lorazepam exposes users to risks of abuse, misuse, and addiction, which can lead to overdose or death. Assess each patient’s risk before prescribing and throughout treatment.
Continued use may lead to clinically significant physical dependence. Abrupt discontinuation or rapid dose reduction can precipitate life-threatening withdrawal reactions including seizures. Use a gradual taper to discontinue. Withdrawal symptoms can appear after as little as one week of treatment and may persist for weeks to more than 12 months.
Patient Counselling
Purpose of Therapy
Lorazepam is prescribed to reduce anxiety, help with anxiety-related sleep difficulty, or as an emergency medication to stop seizures. It works by calming overactive electrical activity in the brain. It is intended for short-term use and is most effective as part of a broader treatment plan that may include psychological therapy. Because your body can become physically dependent on this medication even at prescribed doses, regular reviews with your prescriber are essential.
How to Take
Take lorazepam exactly as prescribed. For immediate-release tablets, doses are usually divided through the day with the largest dose at bedtime. For extended-release capsules (Loreev XR), take once daily in the morning — swallow whole or open and sprinkle on applesauce (do not chew). Do not increase your dose without medical advice. Store securely; this is a controlled substance.
Sources
- Ativan (lorazepam) Tablets. Full Prescribing Information. Bausch Health US, LLC. Revised February 2021. FDA LabelPrimary source for oral dosing, adverse reactions (n≈3,500), drug interactions (valproate, probenecid, clozapine), and contraindications.
- Ativan (lorazepam) Injection. Full Prescribing Information. West-Ward Pharmaceuticals. FDA LabelSource for IV/IM dosing in status epilepticus (4 mg at 2 mg/min) and premedication, plus injection-specific safety data.
- LOREEV XR (lorazepam) Extended-Release Capsules. Full Prescribing Information. Almatica Pharma LLC. Revised August 2021. FDA LabelSource for extended-release dosing, UGT inhibitor interaction guidance, and alcohol-release rate concern.
- Treiman DM, Meyers PD, Walton NY, et al. A comparison of four treatments for generalized convulsive status epilepticus. N Engl J Med. 1998;339(12):792-798. DOIVA Cooperative Study establishing lorazepam as the most effective first-line agent for generalised convulsive status epilepticus.
- Alldredge BK, Gelb AM, Isaacs SM, et al. A comparison of lorazepam, diazepam, and placebo for the treatment of out-of-hospital status epilepticus. N Engl J Med. 2001;345(9):631-637. DOILandmark trial demonstrating superiority of IV lorazepam over placebo and comparable efficacy to diazepam for prehospital status epilepticus.
- Silbergleit R, Durkalski V, Lowenstein D, et al. Intramuscular versus intravenous therapy for prehospital status epilepticus (RAMPART). N Engl J Med. 2012;366(7):591-600. DOIRAMPART trial showing IM midazolam is non-inferior to IV lorazepam for prehospital SE; establishes IV lorazepam as comparator standard.
- Brophy GM, Bell R, Claassen J, et al. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012;17(1):3-23. DOINeurocritical Care Society guidelines recommending IV lorazepam 0.1 mg/kg (max 4 mg) as first-line emergent therapy for convulsive SE.
- Glauser T, Shinnar S, Gloss D, et al. Evidence-based guideline: treatment of convulsive status epilepticus in children and adults. Epilepsy Curr. 2016;16(1):48-61. DOIAmerican Epilepsy Society guideline establishing IV lorazepam as Level A evidence for initial SE treatment in adults.
- By the 2023 American Geriatrics Society Beers Criteria Update Expert Panel. American Geriatrics Society 2023 updated AGS Beers Criteria for potentially inappropriate medication use in older adults. J Am Geriatr Soc. 2023;71(7):2052-2081. DOILists benzodiazepines as potentially inappropriate in older adults due to cognitive impairment, delirium, falls, and fracture risk.
- Sigel E, Ernst M. The benzodiazepine binding sites of GABAA receptors. Trends Pharmacol Sci. 2018;39(7):659-671. DOIComprehensive structural and functional analysis of benzodiazepine binding at GABA-A receptors.
- Greenblatt DJ. Clinical pharmacokinetics of oxazepam and lorazepam. Clin Pharmacokinet. 1981;6(2):89-105. DOIDefinitive PK review establishing lorazepam Vd (1.0–1.3 L/kg), t½ (8–25 h), and demonstrating minimal impact of liver disease on clearance.
- Greenblatt DJ, Schillings RT, Kyriakopoulos AA, et al. Clinical pharmacokinetics of lorazepam. I. Absorption and disposition of oral 14C-lorazepam. Clin Pharmacol Ther. 1976;20(3):329-341. DOILandmark single-dose PK study defining 90% bioavailability, 2-hour Tmax, 12-hour half-life, and 88% urinary recovery as glucuronide.
- Sharma A, Tripp J. Lorazepam. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan–. Updated May 25, 2024. NCBI BookshelfCurrent clinician-oriented review covering indications, dosing across routes, special populations, and pharmacokinetic parameters.