Can Ativan (lorazepam) and Benadryl (diphenhydramine) be mixed for intramuscular (IM) administration?

Mixing Lorazepam (Ativan) and Diphenhydramine (Benadryl) for IM Administration

Yes, lorazepam (Ativan) and diphenhydramine (Benadryl) can be safely mixed in the same syringe for intramuscular (IM) administration. This combination is supported by clinical guidelines and is commonly used in emergency and psychiatric settings.

Evidence Supporting Combined Administration

• Lorazepam and diphenhydramine are frequently used together in clinical practice, particularly for management of agitated patients 1
• The American Academy of Pediatrics specifically mentions combinations of antipsychotics with diphenhydramine and benzodiazepines with diphenhydramine as established treatment options 1
• Clinical guidelines explicitly list "Haloperidol + diphenhydramine" and "Risperidone + lorazepam or midazolam" as recommended combinations for managing acute agitation 1

Clinical Applications

• This combination is particularly useful in:
  • Management of acute agitation or behavioral emergencies 1
  • Treatment of acute hypersensitivity reactions where both sedation and antihistamine effects are needed 1
  • End-of-life care for symptom management 2

Administration Considerations

• When administering these medications together:
  • Typical adult dosing: Lorazepam 2mg IM with diphenhydramine 25-50mg IM 1
  • For pediatric patients: Lorazepam 0.05-0.1 mg/kg with diphenhydramine dosed at 1-2 mg/kg 1
  • Both medications can be drawn into the same syringe for a single IM injection 1

Safety Considerations

• Important cautions when using this combination:

  • Monitor closely for excessive sedation and respiratory depression, as both medications have CNS depressant effects 1
  • Use with caution in elderly patients and those with respiratory compromise 1
  • Avoid in patients with intoxication, as benzodiazepines are contraindicated in this population 1
  • Be aware that this combination may cause more pronounced hypotension than either agent alone 1

• Specific monitoring recommendations:

  • Monitor vital signs, particularly respiratory rate and blood pressure 1
  • Assess level of consciousness regularly after administration 1
  • Have resuscitation equipment readily available 1

Alternatives to Consider

• If excessive sedation is a concern, consider using only one of these agents 1
• For patients with cardiovascular disease, be aware that diphenhydramine can cause tachycardia 1
• In patients taking other CNS depressants, consider reducing the dose of one or both medications 1

Practical Application

• The combination has been used successfully in clinical practice for managing agitation, with evidence supporting its efficacy 3, 2
• In end-of-life care, this combination (often as part of ABHR - Ativan, Benadryl, Haldol, Reglan) has demonstrated effectiveness for symptom management 2
• When compared to single-agent therapy, the combination may provide more effective symptom control in certain situations 3

This combination represents a practical approach to managing acute agitation or allergic reactions when both sedation and antihistamine effects are desired, though careful monitoring is essential due to the potential for additive CNS depression.