What is safer for sundowning in ICU, Seroquel (quetiapine) or Zyprexa (olanzapine)?

Comparing Quetiapine (Seroquel) vs Olanzapine (Zyprexa) for Sundowning in ICU

Quetiapine is safer than olanzapine for managing sundowning in ICU patients due to its more favorable cardiovascular profile and similar efficacy in treating delirium.

Safety Considerations for Antipsychotics in ICU

Cardiovascular Effects

• Recent evidence suggests olanzapine and quetiapine have similar QTc prolongation risk in critically ill patients (8/83 [9.6%] vs 19/129 [14.7%]; P = .28) 1, but quetiapine may have slightly better cardiovascular safety profile overall
• Both medications can cause hypotension (<10%), but quetiapine is preferred in patients with heart failure due to:
  • Benzodiazepine-like hemodynamic effects that are more favorable in cardiac patients
  • Less concern for reduction in cardiac output compared to other sedatives 2

Dosing and Administration

• Quetiapine: Start at 25mg twice daily with gradual titration, especially in elderly or those with hepatic impairment 3
• Olanzapine: Use caution when combining with benzodiazepines due to risk of respiratory depression 3
• Both medications require dose reduction in elderly patients to minimize fall risk 3

Efficacy for ICU Delirium and Sundowning

Evidence for Quetiapine

• A single small prospective, randomized, double-blind, placebo-controlled study showed that ICU patients with delirium who received quetiapine had reduced duration of delirium 2
• Recent research shows similar efficacy between twice daily and bedtime dosing of quetiapine for ICU delirium (3.5 vs 2.5 days to delirium recovery, P = .484) 4
• Quetiapine has been shown to be effective for anxiety with delirium 3

Evidence for Olanzapine

• Limited specific data on olanzapine for ICU delirium compared to quetiapine
• Both medications are considered atypical antipsychotics with similar mechanisms of action

Clinical Decision Algorithm

1. First-line approach: Consider quetiapine 25mg twice daily for sundowning in ICU patients

   • Advantages: Better cardiovascular profile, evidence for efficacy in ICU delirium, flexible dosing options
   • Can be given twice daily or at bedtime with similar efficacy 4

2. Alternative approach: Consider olanzapine if:

   • Patient has history of good response to olanzapine
   • Quetiapine is contraindicated or poorly tolerated

3. Monitoring requirements (for either medication):

   • Daily assessment of mental status and delirium using validated tools
   • QTc monitoring, especially with pre-existing prolongation
   • Blood pressure monitoring for hypotension
   • Extrapyramidal symptoms assessment

Important Caveats and Precautions

• Critical Care Medicine guidelines note that no double-blind, randomized, placebo-controlled trials have definitively established the efficacy or safety of any antipsychotic agent for delirium in ICU patients 2
• Avoid rapid dose escalation which may increase side effect risk 3
• Patients with hepatic impairment require dose adjustments for both medications 3
• Elderly patients require lower doses of both medications 3
• Both medications should be used alongside non-pharmacological interventions including reorientation strategies, sleep optimization, and cognitive stimulation 3

In conclusion, while both medications can be effective for sundowning in the ICU, quetiapine offers a slightly better safety profile with comparable efficacy, making it the preferred choice for most ICU patients experiencing sundowning.