What intramuscular dose of lorazepam and haloperidol should be given to a 54-year-old female with psychiatric illness who is currently agitated?

Intramuscular Dosing for Acute Agitation in a 54-Year-Old Female with Psychiatric Illness

Administer haloperidol 5 mg IM plus lorazepam 2 mg IM as the initial dose for this agitated psychiatric patient. This combination provides superior and more rapid tranquilization compared to either agent alone, with sedation typically achieved within 30-60 minutes 1, 2.

Initial Dosing Regimen

The combination approach is evidence-based and superior to monotherapy:

• Haloperidol 5 mg IM is the standard initial antipsychotic dose for acute agitation, with demonstrated efficacy across multiple randomized trials 1
• Lorazepam 2 mg IM should be administered concurrently with the haloperidol, as this combination produces significantly faster tranquilization than haloperidol alone 1, 2, 3
• The combination showed significantly greater improvement at 1 hour compared to lorazepam alone, with superior agitation control throughout the first 3 hours 1, 2

This combination is supported by the highest quality evidence: A multicenter, prospective, double-blind trial of 98 agitated psychotic patients demonstrated that haloperidol 5 mg plus lorazepam 2 mg achieved the most rapid tranquilization, with significant mean differences on agitation scales at hour 1 compared to either agent alone 2.

Repeat Dosing Protocol

If agitation persists after 30-60 minutes:

• Repeat the same combination: haloperidol 5 mg IM plus lorazepam 2 mg IM 1
• Patients may receive 1-6 injections within 12 hours based on clinical need, though most achieve adequate sedation with 1-2 doses 2
• Maximum benefit occurs at cumulative haloperidol doses of 10-15 mg; doses above 15 mg provide no additional benefit and increase adverse effects 1, 4

Critical Safety Monitoring

Before administering, assess for contraindications:

• Check for QT prolongation: Haloperidol is contraindicated in patients with baseline QTc >500 ms, concomitant QT-prolonging medications, or history of torsades de pointes 4, 5
• Monitor for extrapyramidal symptoms (EPS): The haloperidol group had 20% incidence of EPS, which was 11 times more likely than lorazepam alone 1
• Assess for respiratory depression risk: The combination can cause additive CNS depression, particularly in elderly or medically compromised patients 5

Important Clinical Caveats

Common pitfalls to avoid:

• Do not use haloperidol alone for initial management—the combination with lorazepam is significantly more effective and faster-acting than monotherapy 1, 2, 3
• Do not exceed 15 mg total haloperidol in the first few hours, as higher doses show decreased effectiveness and increased side effects 1, 4
• Watch for akathisia masquerading as persistent agitation—this medication-induced restlessness requires dose reduction, not escalation 5
• Rule out medical causes such as hypoxia, urinary retention, or substance intoxication before attributing ongoing agitation to treatment resistance 5

Alternative Considerations

If the patient has cardiac disease or QTc prolongation:

• Consider IM olanzapine 10 mg as an alternative, which has equivalent efficacy to haloperidol 7.5 mg but with minimal QTc prolongation (only 2 ms vs 7 ms for haloperidol) 4, 6
• IM ziprasidone 20 mg is another option with rapid onset (15 minutes) and notably absent extrapyramidal symptoms, though it should be avoided if QTc >500 ms 6, 5

For cooperative patients who can take oral medication:

• Oral risperidone 2 mg plus oral lorazepam 2 mg is as effective as the IM haloperidol-lorazepam combination, with significantly less excessive sedation 6, 7