Lorazepam

Pronunciation

Pronunciation: lore-AZE-uh-pam
Class: Benzodiazepine

Trade Names

Ativan
- Injection 2 mg/mL
- Injection 4 mg/mL

Lorazepam
- Tablets 0.5 mg
- Tablets 1 mg
- Tablets 2 mg

Lorazepam Intensol
- Oral Solution, Concentrated 2 mg/mL

Apo-Lorazepam (Canada)
PMS-Lorazepam (Canada)

Pharmacology

Potentiates action of GABA, resulting in increased neuronal inhibition and CNS depression, especially in limbic system and reticular formation.

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Pharmacokinetics

Absorption

Absolute bioavailability is 90%. T max is about 2 h. C max is 20 ng/mL after 2 mg dose (dose-dependent).

Distribution

85% protein bound.

Metabolism

Rapidly conjugated at its 3-hydroxy group into lorazepam glucuronide.

Elimination

The t ½ is approximately 12 h for unconjugated lorazepam and approximately 18 h for lorazepam glucuronide.

Indications and Usage

Treatment of anxiety, anxiety associated with depression (oral); preanesthetic medication for sedation/anxiety and decreased recall, status epilepticus (IV).

Unlabeled Uses

Relief of chemotherapy-induced nausea and vomiting; acute alcohol withdrawal; psychogenic catatonia.

Contraindications

Acute narrow-angle glaucoma; intra-arterial administration (injection); hypersensitivity to benzodiazepines.

Dosage and Administration

Antianxiety
Adults

PO Usual dose : 2 to 6 mg/day (range, 1 to 10 mg/day) in divided doses; largest dose at bedtime.

Elderly/Debilitated patients Initial dose

1 to 2 mg/day in divided doses; increase gradually.

Insomnia Caused By Anxiety or Transient Situational Stress
Adults

PO 2 to 4 mg at bedtime.

Preanesthesia
Adults

IM 0.05 mg/kg at least 2 h before procedure (max, 4 mg).

Initial dose

IV 2 mg total or 0.044 mg/kg, whichever is smaller. Do not exceed in patients over 50 yr of age.

For increased lack of recall

0.05 mg/kg (max, 4 mg), 15 to 20 min before procedure.

Status epilepticus
Adults

IV Recommended dose 4 mg given at rate of 2 mg/min. If seizures continue or recur after a 10- to 15-min observation period, an additional 4 mg IV may be administered slowly.

General Advice

Tablets and oral solution
  • Administer prescribed dose without regard to meals but administer with food if GI upset occurs.
  • Tablets may be administered sublingually to patient who has difficulty swallowing tablets.
  • Use calibrated dropper to measure prescribed dose of concentrated oral solution. Add prescribed dose to a liquid (eg, juice, water, soda) or semisolid food (eg, applesauce, pudding); stir for a few seconds then immediately administer entire amount of mixture. Do not prepare and store doses for future use.
Injection
  • For IM or IV administration only. Not for intradermal, SC, or intra-arterial administration.
  • For IM administration, inject undiluted solution deeply into muscle.
  • For IV administration, dilute with equal volume of compatible solution (eg, sterile water for injection, sodium chloride injection or 5% dextrose injection). Do not shake vigorously to avoid air entrapment. Administer directly into a vein or into tubing of existing IV infusion at rate not exceeding 2 mg/min.
  • Do not administer if particulate matter, cloudiness, or discoloration is noted. Discard any unused solution. Do not save for future use.

Storage/Stability

Store tablets at controlled room temperature (59° to 86°F). Protect from moisture. Store injection and oral solution in refrigerator (36° to 46°F). Protect from light.

Drug Interactions

Alcohol/CNS depressants

Additive CNS depressant effects.

Digoxin

Increased serum digoxin concentrations.

Oral contraceptives

Cl rate of lorazepam may be increased.

Rifampin

Pharmacologic effect of lorazepam may be decreased.

Scopolamine

May result in increased incidence of hallucinations, irrational behavior, and sedation.

Theophyllines

May antagonize sedative effects.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

CV collapse; hypotension; phlebitis or thrombosis at IV sites.

CNS

Drowsiness; confusion; ataxia; dizziness; lethargy; fatigue; apathy; memory impairment; disorientation; anterograde amnesia, restlessness; headache; slurred speech; aphonia; stupor; coma; euphoria; irritability; vivid dreams; psychomotor retardation; paradoxical reactions (eg, anger, hostility, mania, insomnia).

Dermatologic

Rash.

EENT

Visual or auditory disturbances; depressed hearing.

GI

Constipation; diarrhea; dry mouth; coated tongue; nausea; anorexia; vomiting; difficulty swallowing.

Hematologic

Leukopenia.

Hepatic

Elevated LDH, ALT, AST, and alkaline phosphatase; hepatic dysfunction, including hepatitis and jaundice.

Respiratory

Partial airway obstruction (injection); respiratory depression.

Miscellaneous

Dependence/withdrawal syndrome (eg, confusion, abnormal perception of movement, depersonalization, muscle twitching, psychosis, paranoid delusions, seizures); pain, burning, redness at IM injection site.

Precautions

Pregnancy

Category D . Avoid use, especially during first trimester because of possible increased risk of congenital malformations. Advise women of childbearing age to use effective contraceptive method. Not recommended during labor and delivery.

Lactation

Undetermined.

Children

Do not use in patients less than 18 yr (IM/IV); safety and efficacy in patients less than 12 yr not established (oral).

Renal Function

Injection is not recommended in these patients. Use oral form with caution.

Hepatic Function

Injection is not recommended in these patients. Use oral form with caution.

Benzyl alcohol

Solution for injection contains 2% benzyl alcohol; avoid use in infants because toxicity may occur.

Drug dependency

Prolonged use can lead to dependence.

Parenteral administration

Primarily for acute states. Keep patients under observation for up to 3 h. Use with extreme care in elderly, very ill patients, or those with limited pulmonary reserve because of the possibility of apnea or cardiac arrest. Do not give to patients in shock or coma or those with acute alcohol intoxication.

Psychiatric disorders

Not intended for use in patients with primary depressive disorder, psychosis, or disorders in which anxiety is not prominent.

Suicide

Use with caution in patients with suicidal tendencies; do not allow access to large quantities of drug.

Overdosage

Symptoms

Ataxia, lethargy, slurred speech, hypotension, respiratory depression, coma, CNS depression.

Patient Information

  • Advise patient or caregiver to read the patient information leaflet before starting therapy and with each refill.
  • Advise patient that medication is usually started at a low dose and then gradually increased until maximum benefit is obtained.
  • Caution patient that medication may be habit forming and to take as prescribed and not to stop taking or change the dose unless advised by health care provider.
  • Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
  • Advise patient or caregiver using concentrated oral solution to measure prescribed dose using calibrated dropper and then add solution to a liquid (eg, juice, water, soda) or semisolid food (eg, applesauce, pudding); stir for a few seconds then immediately take (give) the entire mixture. Caution patient or caregiver not to prepare mixtures ahead of time and store.
  • Advise patient that if a dose is missed to skip that dose and take the next dose at the regularly scheduled time. Caution patient to never take 2 doses at the same time.
  • Advise patient that if medication needs to be discontinued it will be slowly withdrawn unless safety concerns (eg, rash) require a more rapid withdrawal.
  • Instruct patient to avoid alcoholic beverages and other depressants while taking this medication.
  • Advise patient with anxiety to take medication as needed and to seek alternative methods for controlling or preventing anxiety (eg, stress reduction, counseling).
  • Instruct patient to contact health care provider if symptoms (eg, anxiety, panic attacks, seizures) do not appear to be getting better, are getting worse, or if bothersome side effects (eg, drowsiness, memory impairment) occur.
  • Advise patient that drug may cause drowsiness or impair judgment, thinking, or reflexes and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Encourage patient with seizure disorder to carry medical identification (eg, card, bracelet) indicating condition and medication being used to treat.
  • Injection
  • Advise patient or caregiver that medication will be prepared by a health care provider and administered in a health care setting under close observation when oral therapy is not feasible.
  • Caution patient who receives parenteral therapy as an outpatient (eg, outpatient surgery) to use caution while ambulating, and to avoid ingestion of alcohol or other sedatives as well as driving or other hazardous activities for 24 to 48 h.

Copyright © 2009 Wolters Kluwer Health.

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