What is the recommended dosage of Haldol (haloperidol) for treating acute agitation?

Haloperidol Dosing for Acute Agitation

For acute agitation, administer haloperidol 5 mg intramuscularly, which can be combined with lorazepam 2-4 mg IM for faster and more effective sedation. 1

Standard Dosing Approach

Initial Dose

• Haloperidol 5 mg IM is the most commonly studied and effective dose for acute agitation in adults 1
• This dose can be given intramuscularly or orally, with no significant difference in efficacy between routes 1
• Both routes produce significant reduction in agitation within 1-3 hours 1

Combination Therapy (Preferred)

• Adding lorazepam 2-4 mg IM to haloperidol 5 mg produces significantly greater agitation reduction than either drug alone 1
• The combination requires fewer repeat doses and achieves more rapid sedation (within 15-30 minutes) 1, 2
• Benzodiazepines are at least as effective as haloperidol alone and can be safely combined 1, 2

Alternative Combination

• Haloperidol 10 mg combined with promethazine 25-50 mg produces more patients tranquil/asleep at 15,30,60, and 120 minutes compared to lorazepam 4 mg alone 1
• By 4 hours, both regimens achieve similar outcomes (96% tranquil/asleep) 1

Special Population: Older Adults (≥65 years)

For older hospitalized patients, start with haloperidol 0.5 mg IM/IV, which is as effective as higher doses with better safety outcomes. 3, 4

• Low-dose haloperidol (≤0.5 mg) requires no more repeat doses within 4 hours compared to higher doses 3
• Low doses are associated with shorter length of stay, less restraint use, and lower sedation risk 3, 4
• Higher doses (>1 mg) significantly increase sedation risk without improving efficacy 4
• The recommended starting dose of 0.5 mg is frequently ignored in practice, with 37.5% of older patients receiving >1 mg initially 4

Timing and Redosing

• Mean time to sedation with haloperidol 5 mg IM is approximately 28 minutes 1
• If inadequate response, redosing can occur at 30-minute to 1-hour intervals 1
• In comparative studies, haloperidol required fewer repeat doses than some alternatives but more than droperidol 5

Critical Safety Considerations

Extrapyramidal Symptoms (EPS)

• Have diphenhydramine or benztropine immediately available for acute dystonic reactions 2
• No demonstrated EPS symptoms occurred in studies using haloperidol 5 mg, though this risk exists 1
• If intolerable EPS develop, reduce dose or switch to atypical antipsychotic rather than adding long-term anticholinergics 2

Cardiac Monitoring

• Avoid haloperidol if QTc prolongation is present 2
• Haloperidol prolongs QTc interval at steady-state peak concentrations, though typically not exceeding 500 ms 1
• Monitor for neuroleptic malignant syndrome (hyperpyrexia, rigidity, altered mental status, autonomic instability) 2

Contraindications

• Avoid in anticholinergic toxicity or sympathomimetic intoxication, as haloperidol's anticholinergic properties can worsen agitation 2

Comparative Efficacy

• Haloperidol 5 mg produces similar sedation to lorazepam 2 mg, though lorazepam acts more rapidly at 1-3 hours 1
• Droperidol 5 mg requires fewer repeat doses than haloperidol 5 mg (only 36% vs 81% needed second injection at 30 minutes) 5
• Midazolam 5 mg achieves faster sedation (18.3 min) compared to haloperidol 5 mg (28.3 min) 1
• The combination of droperidol/midazolam achieves adequate sedation at 10 minutes in 51.2% of patients versus only 7% with haloperidol/lorazepam 6

Common Pitfalls to Avoid

• Do not escalate to large doses during early treatment (first 1-2 weeks), as this results in excessive dosing and side effects without hastening recovery 2
• Do not use haloperidol monotherapy when combination with benzodiazepines is more effective 1
• Do not use higher doses in older adults assuming better efficacy—this only increases adverse effects 3, 4
• Recognize that immediate effects are primarily sedation, not true antipsychotic response, which takes 4-6 weeks to properly assess 2