What is the recommended approach for switching from aripiprazole (Abilify) 5mg to quetiapine (Seroquel) 150mg?

Switching from Aripiprazole 5mg to Quetiapine 150mg

Use a gradual cross-taper over 2 weeks: start quetiapine at 25mg daily while maintaining aripiprazole 5mg, then titrate quetiapine upward while simultaneously tapering aripiprazole to minimize withdrawal symptoms and allow for receptor adaptation from a partial D2 agonist to a full D2 antagonist. 1

Rationale for Cross-Tapering Strategy

The pharmacological profiles of these medications necessitate a careful transition approach:

• Aripiprazole is a partial D2 agonist while quetiapine is a full D2 antagonist, requiring time for receptor adaptation during the switch 1
• Abrupt discontinuation of aripiprazole could lead to withdrawal symptoms or symptom exacerbation, making gradual tapering essential 1
• Multiple switching strategies have been studied for aripiprazole, including immediate discontinuation, 2-week overlap with taper, and simultaneous taper, all showing comparable safety profiles 2, 3
• However, the gradual cross-titration approach is recommended to minimize treatment failure 1

Specific Switching Protocol

Week 1:

• Start quetiapine 25mg at bedtime (low starting dose to assess tolerability) 4
• Continue aripiprazole 5mg daily (maintain current dose during initial overlap) 2
• Monitor for sedation, orthostatic hypotension, and dizziness (common quetiapine side effects) 4

Week 2:

• Increase quetiapine to 50-100mg at bedtime (gradual titration) 4, 5
• Reduce aripiprazole to 2.5mg daily (begin taper by 50%) 2
• Continue monitoring for adverse effects and symptom stability 3

Week 3:

• Increase quetiapine to 150mg (target dose, can be given once daily or divided BID) 4, 5
• Discontinue aripiprazole completely 2

Week 4 and Beyond:

• Maintain quetiapine 150mg and assess response 5
• Quetiapine can be titrated within the range of 150-750mg/day based on clinical response 5

Critical Monitoring Parameters

During the switching period, monitor closely for:

• Extrapyramidal symptoms and parkinsonism (risk during transition between different D2 receptor profiles) 1
• Sedation and orthostatic hypotension (quetiapine is more sedating than aripiprazole) 4
• Metabolic effects including weight gain (quetiapine has greater metabolic liability than aripiprazole) 4
• Symptom exacerbation or relapse (assess at each dose change) 2, 3
• Withdrawal symptoms from aripiprazole (agitation, anxiety, insomnia, headache) 1

Common Pitfalls to Avoid

• Do not abruptly discontinue aripiprazole without overlap, as this increases risk of symptom exacerbation despite evidence that abrupt switches can be tolerated 5, 3
• Do not start quetiapine at the full 150mg dose immediately, as this increases risk of sedation and orthostatic hypotension, particularly in elderly or frail patients 4
• Do not use quetiapine doses below 150mg long-term for psychotic symptoms, as the therapeutic range for schizophrenia is 150-750mg/day 5
• Avoid combining with other sedating medications during the overlap period without careful monitoring 4

Special Populations

For elderly or frail patients:

• Use lower starting doses (quetiapine 12.5-25mg) and slower titration 4
• Reduce aripiprazole dose more gradually (consider 4-week taper instead of 2 weeks) 1
• Monitor more frequently for falls risk due to sedation and orthostatic hypotension 4

For patients with hepatic or renal impairment:

• Reduce quetiapine doses and titrate more slowly 4
• Consider extending the switching period to 3-4 weeks 1

4, 1, 5, 2, 3