What is the recommended dosing for Seroquel (quetiapine) XR in patients with schizophrenia?

Dosing Seroquel XR in Schizophrenia

For adult patients with schizophrenia, initiate Seroquel XR at 300 mg once daily on Day 1, increase to 600 mg on Day 2, and reach the target therapeutic dose of 800 mg on Day 3, with the effective dose range being 400-800 mg/day administered once daily in the evening. 1

Initial Dosing and Titration

The FDA-approved dosing schedule for Seroquel XR differs significantly from the immediate-release formulation and allows for rapid dose escalation:

• Day 1: Start with 300 mg once daily 2
• Day 2: Increase to 600 mg once daily 2
• Day 3: Increase to 800 mg once daily (maximum dose) 2

This rapid titration schedule has been shown to be well tolerated, with therapeutically effective doses reached by Day 2 2. The once-daily extended-release formulation was specifically developed to improve treatment adherence through simplified dosing 3.

Therapeutic Dose Range

• The effective dose range for Seroquel XR in schizophrenia is 400-800 mg/day administered once daily 1, 2
• Clinical trials demonstrate efficacy across a broad range of symptom domains at doses of 400-800 mg/day 2, 3
• The maximum recommended dose is 800 mg/day 1

Administration Considerations

• Seroquel XR should be administered once daily, preferably in the evening, and can be taken with or without food 1
• The extended-release tablets must be swallowed whole and should not be split, chewed, or crushed 1

Dose Adjustments for Special Populations

Elderly Patients

• Start at a lower dose of 50 mg/day 1
• Increase in increments of 50 mg/day depending on clinical response and tolerability 1
• Use a slower rate of dose titration and consider a lower target dose due to increased risk of hypotensive reactions 1

Hepatically Impaired Patients

• Initiate at 25 mg/day 1
• Increase daily in increments of 25-50 mg/day to reach an effective dose based on clinical response 1

Switching from Immediate-Release to XR Formulation

• Patients stable on quetiapine immediate-release (400-800 mg/day in divided doses) can be switched directly to an equivalent once-daily dose of Seroquel XR (400-800 mg/day) without clinical deterioration or compromise in tolerability 2
• This switch can be accomplished within 4 days without compromising efficacy 2

Maintenance Treatment

• For long-term maintenance, continue the dose on which the patient was stabilized during acute treatment, typically 400-800 mg/day 1
• Patients should be periodically reassessed to determine the need for continued maintenance treatment 1
• Quetiapine XR has demonstrated efficacy in preventing relapse during long-term maintenance treatment and is well tolerated during extended use 2

Common Pitfalls to Avoid

• Do not use the immediate-release titration schedule for Seroquel XR—the XR formulation allows for much more rapid dose escalation (reaching 800 mg by Day 3 versus Day 4-6 for immediate-release) 1, 2
• Do not split or crush extended-release tablets, as this destroys the controlled-release mechanism 1
• Do not underdose—therapeutic efficacy is dose-dependent, with maximum effects occurring at doses ≥400 mg/day 4, 2
• Be aware that while rapid titration is well tolerated, common adverse events include dry mouth, somnolence, and dizziness, which occur more frequently than with placebo 3

Efficacy Assessment

• Each antipsychotic trial should last at least 4-6 weeks at therapeutic doses to properly assess efficacy 5
• If significant positive symptoms persist after 4 weeks at therapeutic doses with good adherence, consider switching to an alternative antipsychotic 5
• After failure of two adequate trials (each 4-6 weeks at therapeutic doses), clozapine should be considered 5