lorazepam (Ativan)
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Introduction
Tradename: Ativan. DEA-controlled substance: class 4.
Indications
- acute management of anxiety
- short-term management of panic attacks
- acute management of seizures, including status epilepticus
- muscle spasm
- management of sedation/agitation in ICU setting
- alcohol withdrawal, delirium tremens
- anticipatory nausea in cancer patients
- management of amphotericin B rigors
- amnesia
- sedation in conjunction with general anesthesia
- mania
- used for insomnia[7]
Dosage
- 0.5-2 mg IV/IM/PO every 6-8 hours[1].
- 1-10 mg/24 hours PO BID/TID[2].
- 0.05 mg/kg IV/IM 4 mg max[2].
- 2 mg SL for nausea.
Tabs: 0.5, 1, 2 mg.
Injection: 2 mg/mL (1 mL, 10 mL), 4 mg/mL (1 mL, 10 mL)
- Infusion solution contains propylene glycol[8]
Tabs: 0.5 mg, 1 mg, 2 mg.
Store injectable form in refrigerator.
Pharmacokinetics
- IM absorption is rapid & complete
- onset of action is 1-5 minutes
- 1/2life is 10-20 hours with acute & chronic use
- metabolized via hydroxylation by the liver
- metabolites are pharmacologically inactive[2]
- does not accumulate
- eliminated in the urine
elimination via liver
elimination via kidney
1/2life = 8-25 hours
protein binding = 88-92 %
Adverse effects
- common (> 10%)
- drowsiness, fatigue, impaired coordination, lightheadedness, memory impairment, insomnia, dysarthria, anxiety, decreased libido, depression, headache, dry mouth, constipation, diarrhea, decreased salivation, nausea, vomiting, tachycardia, chest pain, blurred vision, sweating, rash, increased or decreased appetite, anterograde amnesia
- less common (1-10%)
- uncommon (< 1%)
- menstrual irregularities, blood dyscrasia, reflex slowing urinary incontinence, seizures or liver dysfunction (due to large doses of prolylene glycol), tissue necrosis (if given by intra-arterial route)
- other [3, 5]
- anterograde amnesia, withdrawal, hallucinations, relaxation of the lower esophageal sphincter (GERD), leukopenia[5]
- drug adverse effects of benzodiazepines
- drug adverse effects of psychotropic agents
- drug adverse effects of sedatives
Drug interactions
- disulfiram, nefazodone, fluoxetine, fluvoxamine, cimetidine & grapefruit juice decrease metabolism &/or increase absorption of benzodiazepines
- CNS depressants in combination increase CNS depression
- antiepileptic agents, rifampin increase metabolism of benzodiazpines
- flumazenil antagonizes effects of benzodiazepines
- drug interaction(s) of methadone in combination with benzodiazepines
- drug interaction(s) of benzodiazepines with antidepressants
- drug interaction(s) of benzodiazepines with thiazide diuretics
- drug interaction(s) of antipsycotics with benzodiazepines
- drug interaction(s) of antidepressants with benzodiazepines
- drug interaction(s) of beta-adrenergic receptor antagonists with benzodiazepines
- drug interaction(s) of beta-adrenergic receptor antagonists (except atenolol) with benzodiazepines
- drug interaction(s) of alcoholic beverage with benzodiazepines
- drug interaction(s) of benzodiazepine with opiates
Laboratory
Mechanism of action
- potentiates inhibitory effects of GABA by increasing neuronal membrane permeability to chloride
More general terms
References
- ↑ 1.0 1.1 The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996.
- ↑ 2.0 2.1 2.2 2.3 Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 7
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 5.0 5.1 Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed, WB Saunders, Philadelpha 1995
- ↑ 6.0 6.1 UCLA Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 12-15, 2001
- ↑ 7.0 7.1 Deprecated Reference
- ↑ 8.0 8.1 Geriatric Review Syllabus, 11th edition (GRS11) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2022