What are the guidelines for administering Haldol (haloperidol), Benadryl (diphenhydramine), and Ativan (lorazepam) together intravenously (IV) or intramuscularly (IM)?

Administration Guidelines for Haldol, Benadryl, and Ativan Combination (B-52)

The combination of haloperidol (Haldol), diphenhydramine (Benadryl), and lorazepam (Ativan) administered together IM/IV is an effective approach for managing acute agitation, particularly in emergency settings, but requires careful dosing and monitoring for potential adverse effects. 1

Standard Dosing Recommendations

Adult Dosing

• Haloperidol (Haldol): 5-10 mg IM/IV
• Diphenhydramine (Benadryl): 25-50 mg IM/IV
• Lorazepam (Ativan): 2 mg IM/IV

Pediatric/Adolescent Dosing

• Haloperidol:
  • Adolescent: 0.5-2 mg IM/IV
  • Child: 0.25-0.5 mg IM/IV
• Diphenhydramine: 0.5-1 mg/kg IM/IV (maximum 50 mg)
• Lorazepam: 0.05-0.1 mg/kg IM/IV 1

Administration Guidelines

1. Physical Compatibility: The combination of haloperidol, diphenhydramine, and lorazepam is physically compatible in the same syringe for IM administration 2

2. Administration Sequence:

   • For IV administration: Administer medications sequentially with saline flush between each medication
   • For IM administration: Can be combined in same syringe or given as separate injections

3. Timing of Repeat Dosing:

   • May repeat haloperidol and diphenhydramine every 20-30 minutes if needed
   • Lorazepam may be repeated every 30-60 minutes 1

Clinical Rationale for Combination

This combination provides synergistic effects:

• Haloperidol: Antipsychotic effect for thought disorders and agitation
• Diphenhydramine: Prevents extrapyramidal symptoms (EPS) from haloperidol and provides sedation
• Lorazepam: Rapid anxiolysis and sedation; enhances overall calming effect 1

Research shows this combination is more effective than monotherapy:

• Haloperidol + lorazepam produces significantly greater reduction in agitation than either medication alone 1, 3
• Diphenhydramine prevents acute dystonic reactions from haloperidol 4

Monitoring Requirements

Monitor the following after administration:

• Vital signs: Every 15 minutes for first hour, then hourly until stable
• Respiratory status: Oxygen saturation and respiratory rate
• Cardiac monitoring: For patients with cardiac risk factors or receiving IV administration
• Level of sedation: Using Richmond Agitation-Sedation Scale (RASS) or similar tool
• Extrapyramidal symptoms: Dystonia, akathisia, or other movement disorders 1

Contraindications and Cautions

• Respiratory compromise: Use with extreme caution due to risk of respiratory depression
• Intoxication: Benzodiazepines contraindicated in alcohol or CNS depressant intoxication
• Cardiac conditions: Risk of QT prolongation with haloperidol
• Elderly patients: Use lower doses due to increased sensitivity to side effects
• Pregnancy: Risk-benefit assessment required 1

Potential Adverse Effects

• Respiratory depression: Particularly with lorazepam, increased risk when combined with other sedatives
• Extrapyramidal symptoms: Despite diphenhydramine, can still occur with haloperidol
• Hypotension: Monitor blood pressure, especially with IV administration
• QT prolongation: Risk with haloperidol, especially at higher doses
• Paradoxical excitation: Particularly in pediatric patients or those with developmental disabilities 1

Special Populations

Elderly

• Start with 50% of standard adult dose
• Higher risk of adverse effects including falls, delirium, and sedation 1

Pediatric

• Use caution and lower weight-based dosing
• Higher risk of paradoxical reactions with benzodiazepines 1

Palliative Care

• Combination particularly useful for terminal agitation or delirium
• Evidence supports improved comfort perception by caregivers and nurses 3

Common Pitfalls to Avoid

1. Oversedation: Starting with too high doses in elderly or medically compromised patients
2. Inadequate monitoring: Failure to monitor respiratory status after administration
3. Misdiagnosis: Treating delirium with this combination without addressing underlying causes
4. Prolonged use: This combination is intended for acute management, not long-term therapy
5. Drug interactions: Failure to account for other medications that may potentiate sedation or QT prolongation

This combination, sometimes called the "B-52" in clinical settings, should be used judiciously with appropriate monitoring and only after less invasive approaches have been attempted when possible.