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# Lorazepam
## Overview
Lorazepam is a high-potency, intermediate-acting benzodiazepine. It acts as a positive allosteric modulator of the $\text{GABA}_\text{A}$ receptor, enhancing the inhibitory effects of GABA in the central nervous system. It has a relatively slow onset but a predictable duration of action, with no active metabolites.
## Primary Indications
* Anxiety disorders (short-term management)
* Status epilepticus
* Insomnia
* Preoperative sedation/anxiolysis
* Prevention/treatment of alcohol withdrawal
## Adult Dosing
* **Anxiety:** 1–3 mg orally daily in divided doses. Max: 10 mg/day.
* **Insomnia:** 2–4 mg orally at bedtime.
* **Status Epilepticus:** 4 mg IV bolus; may repeat once after 10–15 minutes if seizures persist.
* **Preoperative Sedation:** 0.05 mg/kg (up to 4 mg) IM or slow IV (2 mg/min) 2 hours before surgery.
## Pediatric Dosing
* **Status Epilepticus:** 0.1 mg/kg slow IV/IO (max single dose 4 mg). May repeat once after 10–15 minutes if necessary.
* **Sedation/Anxiolysis:** 0.05 mg/kg slow IV/IM (max 2 mg).
* *Note: Ensure slow administration to prevent respiratory depression.*
## Dose Adjustments
* **Geriatric/Debilitated:** Start at lower doses (e.g., 0.5 mg daily) due to increased sensitivity and risk of falls.
* **Hepatic/Renal Impairment:** Lorazepam is preferred over other benzodiazepines in severe hepatic impairment because it undergoes direct glucuronidation (no active metabolites); however, dose reduction is still recommended in hepatic insufficiency.
## Contraindications
* Known hypersensitivity to benzodiazepines.
* Acute narrow-angle glaucoma.
* Severe respiratory insufficiency or untreated sleep apnea.
* Myasthenia gravis.
## Adverse Effects
* **Common:** Sedation, dizziness, ataxia, fatigue, anterograde amnesia.
* **Serious:** Paradoxical reactions (agitation, aggression), severe respiratory depression (especially when co-administered with opioids), physiological dependence, and withdrawal syndrome upon abrupt discontinuation.
## Key Drug Interactions
* **CNS Depressants:** Co-administration with opioids, alcohol, or other sedatives creates a synergistic risk of fatal respiratory depression.
* **Valproic Acid:** May inhibit glucuronidation, potentially elevating lorazepam concentrations.
* **Probenecid:** May increase the half-life of lorazepam.
## Monitoring
* **Safety:** Monitor respiratory rate, level of sedation, and blood pressure (particularly during IV administration).
* **Long-term:** Assess for symptoms of dependence, tolerance, or misuse.
* **Status Epilepticus:** Continuous EEG monitoring and proactive airway management if seizure control requires repeated or high-dose administration.
## Clinical Pearls
* **Propylene Glycol Toxicity:** Frequent or prolonged infusion of IV lorazepam may lead to propylene glycol accumulation, causing metabolic acidosis and acute kidney injury.
* **Storage:** IV preparations must be refrigerated and protected from light.
* **Discontinuation:** Always taper to prevent withdrawal seizures or rebound anxiety.
* **Reversal:** Flumazenil is available as an antidote, but should be used with extreme caution in chronic benzodiazepine users to avoid precipitating acute withdrawal seizures.
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**Educational Disclaimer:** This information is for educational purposes only. Always verify dosages, contraindications, and drug interactions against current institutional protocols, primary literature, and the official manufacturer package insert before prescribing or administering medication.
