EpilepsyRx

Lorazepam

Ativan

DailyMed-verified antiseizure indications

Indication / use

Label / evidence summary
Ativan injection: treatment of status epilepticus in adults. Pediatric safety and effectiveness for status epilepticus have not been established in the label.
Role
Rescue / acute treatment
Class
1,4-benzodiazepine

Indications checked 26 September 2026. Product, route, age, and treatment-role limits apply. A DailyMed listing alone does not establish FDA approval.

Formulations & strengths

U.S. products unless another country is named. Strengths are per unit or stated volume.

Brand & formulation labels

Each link names the product and formulation it covers. Archived labels do not establish current availability.

Dosing & administration

Adult / product-specific schedule
4 mg IV at ≤2 mg/min; if seizures persist/recur, may repeat 4 mg after 10–15 minutes.
Pediatric
The Ativan injection label does not establish pediatric safety and effectiveness for status epilepticus; no pediatric seizure regimen is listed here.
Titration / repeat dosing
No maintenance titration for emergency use. Monitor airway, respiration and blood pressure; escalate persistent status promptly.

Dose adjustment & concentrations

Renal impairment
Use caution with repeated doses.
Hepatic impairment
Caution in severe insufficiency.
Serum reference information
No routine serum target for acute treatment

Safety

Boxed warning
Boxed: opioid-associated respiratory depression, abuse/misuse/addiction, and dependence/withdrawal. No reliable single incidence estimate; risk depends on exposure and co-sedatives. Avoid abrupt withdrawal after repeated use.
Contraindications
Ativan injection: benzodiazepine/vehicle hypersensitivity, acute narrow-angle glaucoma, sleep apnea, severe respiratory insufficiency (label exception for mechanically ventilated patients); intra-arterial administration.
Serious precautions & monitoring
Low CYP burden does not mean low sedative risk. IV access and respiratory support are required.

Common / selected adverse effects

  • Active-controlled status trial (85 lorazepam patient-episodes): somnolence; respiratory failure

Drug interactions: toxicity & clinical action

Partner / combinationClinical effectClinical action
Valproate / probenecidReduced lorazepam clearance and prolonged sedation.The label recommends approximately 50% lorazepam dose reduction; apply the correct setting-specific regimen.
Opioids / other sedativesAdditive respiratory depression and hypotension.Monitor airway, breathing and sedation; limit combined doses.

Pregnancy & contraception

Fetal / neonatal risk
Lorazepam exposure late in pregnancy or during labor can cause neonatal sedation, respiratory depression or withdrawal. Published benzodiazepine observational data do not show a clear major-malformation association.
Pregnancy / postpartum monitoring
Monitor exposed newborns for sedation, feeding difficulty and withdrawal; neonatal clearance is slower than adult clearance.

Clinical evidence

Research summaries describe studied populations and outcomes; they do not add indications or constitute treatment recommendations.

Direct pivotal trial Guideline-supported off-label use

Trial summary

Study design / duration
Randomized, double-blind, Phase 3 noninferiority prehospital trial; 893 participants ≥13 kg. Lorazepam 4 mg IV (>40 kg) or 2 mg (13–40 kg); comparator midazolam 10/5 mg IM.
Primary endpoint
No single pivotal endpoint is identified in the cited source.
Results
RAMPART: IV lorazepam achieved seizure cessation without rescue before ED arrival in 63.4%, versus 73.4% with IM midazolam. Route/access delay contributed; this does not establish intrinsic drug superiority.

Trial publications

Comparative evidence

Findings
RAMPART prehospital status trial: seizures absent without rescue treatment at ED arrival in 73.4% IM midazolam vs 63.4% IV lorazepam.

Mechanism of action

  • A 1,4-benzodiazepine that enhances GABA-dependent gating of benzodiazepine-sensitive GABA-A chloride channels at the classical α/γ subunit-interface site. This is distinct from the GABA-binding site and from GABA-B receptors.
  • The classical teaching is increased opening/burst frequency for benzodiazepines versus longer openings for barbiturates. Single-channel behavior depends on preparation and conditions, so this is a useful distinction rather than an absolute kinetic rule.
  • Route, onset, duration, active metabolites and clearance distinguish these drugs clinically, but those pharmacokinetic differences are not separate receptor mechanisms.

Pharmacology

Adult values unless specified. Vd/F denotes apparent oral distribution volume.

Pharmacokinetics

Bioavailability
IV: 100% by definition. Oral: approximately 90% absolute bioavailability. IM injection is completely absorbed in the product-label study.
Elimination half-life
Approximately 14 ± 5 hours after parenteral administration; oral mean approximately 12 hours.
Volume of distribution
Approximately 1.3 L/kg (injection label).
Active metabolite(s)
None: lorazepam glucuronide is inactive.
Active-metabolite half-life
Not applicable — no clinically established active metabolite.
Protein binding
~91%
Metabolism / elimination
Direct glucuronidation

The inactive glucuronide accumulates in renal impairment; this is distinct from accumulation of an active metabolite.

Molecular structure

Molecular structure of Lorazepam
Principal compound; salt and product forms may differ.
NIH PubChem structure and record ↗

Product history

Initial U.S. approval
1977 (oral lorazepam)
Market / formulation history
1977 (oral); 1980 (Ativan injection)
Brands
Ativan
Manufacturer / marketer
Ativan injection: Hikma; oral brand: Bausch Health
Generic availability
Yes: injection and oral products.
Related drugs
1,4-benzodiazepine; no active oxidative metabolite, unlike diazepam.

Sources & review status

Representative sources are selected product labels, not an exhaustive list of generic manufacturers. Consult the exact product and formulation prescribed. Brand-name package inserts are linked separately.

Brand references: Ativan tablets ↗ · Ativan injection ↗

Indications and DailyMed PDFs checked: 2026-09-26. Other profile sources reviewed: 2026-09-15 · label revision noted at that review: 4/2023. This is a draft reference; final review is pending.

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