LORAZEPAM

(lor-a'ze-pam)

Ativan
Classifications: anxiolytic; sedative-hypnotic; benzodiazepine;
Therapeutic: antianxiety; sedative-hypnotic
Pregnancy Category: D
Controlled Substance: Schedule IV

Availability

0.5 mg, 1 mg, 2 mg tablets; 2 mg/mL oral solution; 2 mg/mL, 4 mg/mL injection

Action

Most potent of the available benzodiazepines. Effects (antianxiety, sedative, hypnotic, and skeletal muscle relaxant) are mediated by the inhibitory neurotransmitter GABA. Action sites are thalamic, hypothalamic, and limbic levels of CNS.

Therapeutic Effect

Antianxiety agent that also causes mild suppression of REM sleep, while increasing total sleep time.

Uses

Management of anxiety disorders and for short-term relief of symptoms of anxiety. Also used for preanesthetic medication to produce sedation and to reduce anxiety and recall of events related to day of surgery; for management of status epilepticus.

Unlabeled Uses

Chemotherapy-induced nausea and vomiting.

Contraindications

Known sensitivity to benzodiazepines; acute narrow-angle glaucoma; primary depressive disorders or psychosis; COPD; children <12 y (PO preparation); coma, shock, sleep apnea; acute alcohol intoxication; dementia; pregnancy (category D), and lactation.

Cautious Use

Renal or hepatic impairment; renal failure; organic brain syndrome; myasthenia gravis; narrow-angle glaucoma; pulmonary disease; mania; psychosis; suicidal tendency; history of seizure disorders; GI disorders; older adult and debilitated patients; limited pulmonary reserve.

Route & Dosage

Antianxiety
Adult: PO 2–6 mg/d in divided doses (max: 10 mg/d)
Geriatric: PO 0.5–1 mg/d (max: 2 mg/d)
Child: PO/IV 0.05 mg/kg q4–8h (max: 2 mg/dose)

Insomnia
Adult: PO 2–4 mg at bedtime
Geriatric: PO 0.5–1 mg h.s.

Premedication
Adult: IM 2–4 mg (0.05 mg/kg) at least 2 h before surgery IV 0.044 mg/kg up to 2 mg 15–20 min before surgery
Child: PO/IV/IM 0.05 mg/kg (range: 0.02–0.09 mg/kg)

Status Epilepticus
Adult: IV 4 mg injected slowly at 2 mg/min, may repeat dose once if inadequate response after 10 min

Administration

Oral

Increase the evening dose when higher oral dosage is required, before increasing daytime doses.

Intramuscular

Injected undiluted, deep into a large muscle mass.

Intravenous

IV administration to neonates, infants, children: Verify correct IV concentration and rate of infusion with physician.
Patients >50 y may have more profound and prolonged sedation with IV lorazepam (usual max: initial dose of 2 mg).

PREPARE: Direct: Prepare lorazepam immediately before use. Dilute with an equal volume of sterile water, D5W, or NS.

ADMINISTER: Direct: Inject directly into vein or into IV infusion tubing at rate not to exceed 2 mg/min and with repeated aspiration to confirm IV entry. Take extreme precautions to PREVENT intraarterial injection and perivascular extravasation.

INCOMPATIBILITIES Solution/additive: Dexamethasone. Y-site: Aldesleukin, aztreonam, fluconazole, foscarnet, gallium, idarubicin, imipenem/cilastatin, omeprazole, ondansetron, sargramostim, sufentanil, thiopental, TPN with albumin.

Keep parenteral preparation in refrigerator; do not freeze.
Do not use a discolored solution or one with a precipitate.

Adverse Effects (≥1%)

Body as a Whole: Usually disappear with continued medication or with reduced dosage. CNS: Anterograde amnesia, drowsiness, sedation, dizziness, weakness, unsteadiness, disorientation, depression, sleep disturbance, restlessness, confusion, hallucinations. CV: Hypertension or hypotension. Special Senses: Blurred vision, diplopia; depressed hearing. GI: Nausea, vomiting, abdominal discomfort, anorexia.

Interactions

Drug: Alcohol, cns depressants, anticonvulsants potentiate CNS depression; cimetidine increases lorazepam plasma levels, increases toxicity; lorazepam may decrease antiparkinsonism effects of levodopa; may increase phenytoin levels; smoking decreases sedative and antianxiety effects. Herbal: Kava, valerian may potentiate sedation.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: 1–5 min IV; 15–30 min IM. Peak: 60–90 min IM; 2 h PO. Duration: 12–24 h. Distribution: Crosses placenta; distributed into breast milk. Metabolism: Not metabolized in liver. Elimination: In urine. Half-Life: 10–20 h.

Nursing Implications

Assessment & Drug Effects

Have equipment for maintaining patent airway immediately available before starting IV administration.
IM or IV lorazepam injection of 2–4 mg is usually followed by a depth of drowsiness or sleepiness that permits patient to respond to simple instructions whether patient appears to be asleep or awake.
Supervise ambulation of older adult patients for at least 8 h after lorazepam injection to prevent falling and injury.
Lab tests: Assess CBC and liver function tests periodically for patients on long-term therapy.
Supervise patient who exhibits depression with anxiety closely; the possibility of suicide exists, particularly when there is apparent improvement in mood.

Patient & Family Education

Do not drive or engage in other hazardous activities for a least 24–48 h after receiving IM injection of lorazepam.
Do not drink large volumes of coffee. Anxiolytic effects of lorazepam can be significantly altered by caffeine.
Do not consume alcoholic beverages for at least 24–48 h after an injection and avoid when taking an oral regimen.
Notify physician if daytime psychomotor function is impaired; a change in regimen or drug may be needed.
Terminate regimen gradually over a period of several days. Do not stop long-term therapy abruptly; withdrawal may be induced with feelings of panic, tonic–clonic seizures, tremors, abdominal and muscle cramps, sweating, vomiting.
Do not self-medicate with OTC drugs; seek physician guidance.
Discuss discontinuation of drug with physician if you wish to become pregnant.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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