Lorazepam — Ativan — is the workhorse benzodiazepine for acute psychiatric situations. It is the most versatile BZD in routine practice: available oral, sublingual, intramuscular, and intravenous; with predictable kinetics; with no active metabolites that complicate hepatic impairment; and with a half-life around 12-18 hours that balances onset against accumulation.
- Class
- Intermediate-acting benzodiazepine
- Mechanism
- GABA-A positive allosteric modulator
- Typical dose
- 0.5-2 mg every 6-8 hours; IV/IM 1-2 mg for acute agitation, status epilepticus, alcohol withdrawal
- Half-life
- ~12-18 hours
- FDA indications
- Anxiety, acute agitation, alcohol withdrawal, status epilepticus, catatonia, procedural anxiolysis
- Key adverse effects
- Sedation, cognitive impairment, ataxia, respiratory depression at high doses or with opioids, tolerance, dependence
Black box: Concomitant opioid use; abuse potential and dependence
Multiple formulations (PO, SL, IM, IV) make it versatile. No active metabolites — useful in hepatic impairment (vs. diazepam). IM/IV for acute agitation often combined with haloperidol. First-line for catatonia (often dramatically effective). Alcohol withdrawal: lorazepam (or chlordiazepoxide for longer-acting).
For acute agitation in the ED or inpatient unit, IM lorazepam is the standard adjunct to antipsychotics. The classic combination — IM haloperidol 5 mg plus IM lorazepam 2 mg — produces calming effect within 30 minutes with mechanism synergy.
For alcohol withdrawal, lorazepam (or chlordiazepoxide for less severe outpatient cases) is first-line. The Clinical Institute Withdrawal Assessment (CIWA) protocol uses lorazepam doses titrated to symptoms; severe withdrawal can require very high doses. In hepatic impairment from cirrhosis, lorazepam's glucuronidation-only metabolism makes it the preferred BZD — diazepam and chlordiazepoxide accumulate dangerously in liver disease, but lorazepam, oxazepam, and temazepam don't.
Lorazepam is an intermediate-acting benzodiazepine whose simple, extra-hepatic metabolism makes it a workhorse in medically complex patients.
Mechanism note: Lorazepam's glucuronidation metabolism — no CYP step, no active metabolites — makes it the predictable, interaction-light benzodiazepine for hepatic impairment and medically complex patients.
For status epilepticus, IV lorazepam 4 mg is first-line per current guidelines. For procedural anxiolysis, oral or sublingual lorazepam works.
One distinctive use that deserves mention: catatonia. Lorazepam at 1-2 mg IM or IV is both diagnostic and therapeutic for catatonia. The response can be dramatic — patients with profound psychomotor immobility who haven't spoken for days will begin moving and talking within 30 minutes. If lorazepam works, continue scheduled lorazepam every 6-8 hours while the underlying cause is addressed. If lorazepam fails, ECT is highly effective. Catatonia is treatable, and missing it has serious consequences; lorazepam challenge is the test.
Lorazepam has the qualities you want in an acute BZD: predictable, versatile, well-tolerated, accessible across hepatic conditions. For acute settings, it is the standard tool.
- Cost
- Generic: ~$10-25/month.
- Generic status
- Generic for decades.
- Formulary typical
- Tier 1 generic.
- Access friction
- Schedule IV scheduling. IM/IV forms universally available in acute settings.
Prescriber tip: Workhorse for acute psychiatric situations. For outpatient use, write small quantities, PDMP review at every prescription. Document indication and time-limited plan.