When to use quetiapine (Seroquel) vs aripiprazole (Abilify) as an adjunct in treatment?

Choosing Between Quetiapine vs Aripiprazole as Adjunctive Treatment

When choosing between quetiapine and aripiprazole as adjunctive treatments, select aripiprazole for maintenance treatment of bipolar disorder and for patients concerned about sedation or weight gain, while quetiapine is preferred for patients with insomnia, agitation, or when sedation is desired.

Comparative Side Effect Profiles

The choice between these two atypical antipsychotics should be guided by their distinct side effect profiles:

Aripiprazole (Abilify)

• Less sedating than quetiapine
• Lower risk of metabolic effects and weight gain
• Higher risk of akathisia (NNH of 6) 1
• FDA-approved for maintenance treatment of bipolar I disorder as both monotherapy and adjunctive therapy 2
• Particularly effective at preventing manic relapses (fewer manic episodes compared to placebo in clinical trials) 2

Quetiapine (Seroquel)

• More sedating (NNH for somnolence of 5-6) 1
• Higher risk of weight gain, metabolic effects, and orthostatic hypotension
• Dry mouth is common (reported in up to 44% of patients) 3
• Effective for acute mania in adults 4
• Useful when sedation is desired or for patients with insomnia

Clinical Scenarios for Preferring Aripiprazole

Aripiprazole is the preferred choice when:

1. Long-term maintenance treatment is needed - Superior efficacy in preventing bipolar relapses, particularly manic episodes 2
2. Patient is concerned about sedation - Less sedating than quetiapine, making it better for daytime use
3. Weight gain is a significant concern - Lower risk of metabolic effects
4. Patient has orthostatic hypotension - Less likely to cause this side effect
5. Patient has a history of substance abuse - May help with comorbid substance use disorders

Clinical Scenarios for Preferring Quetiapine

Quetiapine is the preferred choice when:

1. Insomnia is a prominent symptom - Sedating properties can be beneficial
2. Agitation needs to be controlled - Sedating effect helps manage agitation
3. Patient has akathisia with other antipsychotics - Lower risk of akathisia than aripiprazole
4. Adjunctive treatment for depression - Effective as adjunct to SSRIs or SNRIs for major depressive disorder 5
5. Elderly patients with delirium - Can be used at lower doses (25mg) for management of delirium 4

Dosing Considerations

Aripiprazole

• Initial dose: 5-10 mg/day
• Maintenance dose: 10-30 mg/day
• For adjunctive treatment in bipolar disorder: typically starts at 15 mg/day 2

Quetiapine

• Initial dose: 25-50 mg/day (immediate release)
• For adjunctive treatment in depression: 150-300 mg/day (extended release) 6
• For elderly patients: start with lower doses (12.5-25 mg) 4

Special Populations

Elderly Patients

• Start with lower doses for both medications
• Quetiapine: 12.5-25 mg
• Aripiprazole: 2.5-5 mg
• Monitor closely for orthostatic hypotension with quetiapine 4

Patients with Bipolar Disorder

• Aripiprazole has stronger evidence for maintenance treatment and prevention of manic episodes 2
• Both are approved for acute mania in adults 4

Patients with Major Depression

• Both can be effective as adjunctive therapy to antidepressants
• Quetiapine XR at 150-300 mg/day shows significant improvement in depressive symptoms when added to SSRIs or SNRIs 5
• NNT for response with adjunctive aripiprazole ranges from 7-14 1

Monitoring Recommendations

For both medications:

• Baseline metabolic parameters (weight, lipids, glucose)
• Regular monitoring of weight and metabolic parameters
• Assess for extrapyramidal symptoms
• Monitor for sedation and orthostatic hypotension (especially with quetiapine)
• Evaluate QTc interval at baseline and with dose increases

Common Pitfalls to Avoid

1. Overlooking akathisia with aripiprazole - Monitor closely, especially in the first few weeks
2. Underestimating sedation with quetiapine - Warn patients about driving and operating machinery
3. Abrupt discontinuation - Both should be tapered gradually to avoid withdrawal symptoms
4. Ignoring drug interactions - Both interact with medications affecting cytochrome P450 enzymes
5. Inadequate metabolic monitoring - Regular monitoring is essential for both medications

In conclusion, the choice between quetiapine and aripiprazole should be guided by the specific clinical scenario, patient's symptom profile, and potential side effects that would be most problematic for the individual patient.