Lorazepam

Antidepressant Drug

Drug class: Benzodiazepine, BDZs

Lorazepam (ATIVAN)（中文：勞拉西泮）

Common Strengths of Lorazepam

Lorazepam are available in the following strengths:

• Tablets: 0.5 mg, 1 mg, 2 mg
• Oral solution: 2 mg/mL
• Injection solution: 2 mg/mL, 4 mg/mL

Drug Trade Names of Lorazepam

Ativan

Drug Usage

• Anxiety disorders
• Insomnia due to anxiety or stress
• Status epilepticus
• Pre-operative sedation

Mechanism of Action

Lorazepam enhances the effect of GABA, the main inhibitory neurotransmitter in the brain, by binding to GABA_A receptors. This results in sedative, anxiolytic, muscle relaxant, and anticonvulsant effects.

Route of Administration

Oral (tablets, solution), intramuscular injection, intravenous injection

Dosages

• For anxiety: 2-3 mg/day in divided doses, maximum 10 mg/day
• Elderly or debilitated patients: Start with 1 to 2 mg/day in divided doses

Side Effects

Frequency	Adverse reactions
Common	Sedation (15.9%)
	Dizziness (6.9%)
	Weakness (4.2%)
	Unsteadiness (3.4%)
	Drowsiness
	Fatigue
	Confusion
	Amnesia
	Ataxia
	Respiratory depression
	Hypotension
	Vertigo
	Visual disturbances
	Dysarthria
	Nausea
	Constipation
The incidence of sedation and unsteadiness increase with age. Lorazepam can impair both explicit and implicit memory more profoundly than other benzodiazepines.
Serious	Respiratory depression and failure
	Seizures
	Suicidal ideation/attempt
	Dependence and abuse
	Tachycardia
	Blood dyscrasias
	Jaundice
	Paradoxical reactions (hyperactive and aggressive behavior)
	Withdrawal symptoms if abruptly discontinued after long-term use
Lorazepam's effects are dose-dependent. Using the smallest effective dose minimizes adverse effects. Sedative drugs like lorazepam have been associated with increased mortality risk.
Note: Lorazepam carries risks of dependence and withdrawal. It should be used under close medical supervision and not stopped abruptly.

Pharmacokinetics

• Onset: 1 to 5 minutes (IV), 15 to 30 minutes (IM), 1 to 2 hours (Oral)
• Duration: 6 to hours
• Half-life: 12 to 18 hours
• Metabolism: Lorazepam is primarily metabolized in the liver through glucuronidation to form an inactive metabolite. This metabolic pathway dose not involve cytochrome P450 enzymes, making it relatively unaffected by liver dysfunction.
• Excretion: It is primarily excreted in the urine.

Drug Precautions

Pregnancy

Potential risk of congenital malformations; use only if benefits outweigh risks.

Breastfeeding

Excreted in breast milk; not recommended.

Children and Elderly

Not recommended for children under 12; lower doses for elderly.

Monitoring Requirements

Respiratory rate, sedation level, signs of abuse/dependence.

Drug Interactions

Avoid alcohol, opioids, and other CNS depressants.

• Central Nervous System (CNS) Depressants:
  • Opioids, alcohol, barbiturates, antipsychotics, sedatives/hypnotics, anxiolytics, antidepressants, narcotic analgesics, sedative antihistamines, anticonvulsants, and anesthetics can increase the CNS-depressant effects of lorazepam, leading to excessive sedation and respiratory depression.
  • Concomitant use of lorazepam with opioids can cause serious, life-threatening, and fatal respiratory depression.
• Valproate:
  • Concurrent administration of lorazepam with valproate results in increased plasma concentrations and reduced clearance of lorazepam. Lorazepam dosage should be reduced by approximately 50%.
• Theophylline or Aminophylline:
  • Administration of theophylline or aminophylline may reduce the sedative effects of lorazepam.
• Clozapine:
  • Concomitant use of clozapine and lorazepam may produce marked sedation, excessive sailvation, hypotension, ataxia, delirium, and respiratory arrest.

FAQ

How Should I Take Lorazepam?

Take exactly as prescribed, usually 2 to 3 times daily with or without food.

What Should I Avoid While Taking?

Alcohol, driving/operating machinery until effects are known

What Happens if I Miss a Dose?

Take as soon as remembered if not close to the next dose; do not double up.