What are the recommended intravenous (IV) medications for acute anxiety?

Recommended IV Medications for Acute Anxiety

For acute anxiety in adults, intravenous benzodiazepines are the first-line treatment, with midazolam 2.5-5 mg IV or lorazepam 0.5-1 mg IV being the preferred agents. 1, 2, 3

First-Line IV Medications

Midazolam

• Dosing for adults:
  • Initial dose: 2.5-5 mg IV given slowly over 2-3 minutes 2
  • Allow 2-3 minutes to evaluate sedative effect before repeating dose
  • Maximum: Generally not exceeding 10 mg total 2
  • For elderly or debilitated patients: Use lower doses (reduce by 50%)

Lorazepam

• Dosing for adults:
  • Initial dose: 0.5-1 mg IV (maximum 4 mg in 24 hours) 1, 3
  • For elderly or debilitated patients: 0.25-0.5 mg IV (maximum 2 mg in 24 hours) 1
  • Administer slowly (2 mg/minute)
  • Can be repeated if needed after 15-20 minutes

Special Considerations

Patient-Specific Factors

• Renal impairment:

  • Prefer lorazepam over midazolam
  • Reduce midazolam dose by 50% if eGFR <30 mL/min 1

• Hepatic impairment:

  • Reduce doses of both medications
  • Midazolam metabolism is more affected than lorazepam

• Elderly patients:

  • Start with 50% of standard dose for both medications
  • Higher risk of paradoxical reactions, respiratory depression, and falls 1

Monitoring Requirements

• Continuous monitoring of:
  • Oxygen saturation
  • Respiratory rate
  • Blood pressure
  • Level of sedation
• Have resuscitation equipment readily available

Potential Adverse Effects

Common Adverse Effects

• Respiratory depression (especially when combined with opioids)
• Hypotension
• Paradoxical agitation/excitation
• Oversedation
• Amnesia

Serious Adverse Effects

• Respiratory arrest
• Cardiovascular collapse
• Increased risk when combined with other CNS depressants

Clinical Pearls

• Titrate carefully: Always titrate to the minimum effective dose to avoid oversedation 2
• Avoid rapid administration: Administer slowly to prevent respiratory depression and hypotension 2, 3
• Flumazenil availability: Consider having flumazenil available for reversal of severe benzodiazepine-induced respiratory depression 2
• Combination therapy: When benzodiazepines are insufficient alone, consider adding haloperidol for patients with severe agitation or delirium 1
• Caution with combinations: There is an increased risk of respiratory depression when benzodiazepines are combined with opioids or other sedatives 2, 4

Alternative Options

For Specific Situations

• Delirium with agitation:

  • Haloperidol 0.5-1 mg IV (maximum 10 mg daily, or 5 mg daily in elderly) 1
  • Consider adding benzodiazepine if patient remains agitated

• Alcohol or benzodiazepine withdrawal:

  • Benzodiazepines are treatment of choice 1
  • Lorazepam preferred due to more predictable metabolism

• Propofol consideration:

  • May be considered for brief procedures at subhypnotic doses (20 mg)
  • As effective as midazolam 2 mg for reducing pre-procedural anxiety 5
  • Requires more careful monitoring due to risk of respiratory depression

Remember that while IV benzodiazepines are effective for acute anxiety, they should be used for the shortest duration possible to minimize risks of dependence and adverse effects.