Starting Dose of Quetiapine XR
The recommended starting dose of Quetiapine XR is 50 mg once daily, with gradual titration to an effective dose based on clinical response and tolerability. 1
Dosing Protocol for Quetiapine XR
Initial Dosing
- Begin with 50 mg once daily, administered in the evening
- For elderly patients or those with hepatic impairment, start with a lower dose of 25 mg once daily 1
Titration Schedule
- Increase by 50 mg increments daily
- Target dose range: 400-800 mg once daily for schizophrenia
- Lower target doses (300-400 mg daily) may be appropriate for other indications
- Rapid dose escalation is possible (300 mg on day 1,600 mg on day 2, and 800 mg on day 3) if clinically indicated and tolerated 2
Administration Considerations
- Administer once daily, preferably in the evening due to sedative effects
- Can be taken with or without food, but high-fat meals may increase absorption
- Extended-release formulation should be swallowed whole, not crushed or chewed
Clinical Advantages of Quetiapine XR
- Once-daily dosing improves medication adherence compared to multiple daily dosing regimens 2
- Extended-release formulation provides more stable plasma concentrations throughout the 24-hour period
- Equally effective as immediate-release formulation but with simplified dosing schedule 3
- Allows for more rapid dose titration compared to immediate-release formulation 2
Monitoring During Initiation
- Watch closely for orthostatic hypotension, particularly during initial titration
- Monitor for sedation and somnolence, especially during the first few days
- Assess for metabolic effects (weight, blood glucose, lipids)
- Monitor for QTc interval prolongation in high-risk patients
Common Side Effects to Anticipate
- Sedation and somnolence (17.5% vs 10.7% with placebo) 4
- Dizziness (9.6% vs 4.4% with placebo) 4
- Dry mouth, constipation, and dyspepsia
- Transient liver enzyme elevations 4
Important Clinical Considerations
- Quetiapine XR has a favorable side effect profile with low risk of extrapyramidal symptoms 1
- No routine blood monitoring is required (unlike clozapine)
- Does not significantly elevate prolactin levels 4
- Weight gain of approximately 2.1 kg may occur in short-term treatment 4
Quetiapine XR's once-daily dosing regimen simplifies treatment while maintaining efficacy comparable to multiple daily dosing of immediate-release formulations. The extended-release formulation allows for more rapid dose titration while minimizing side effects, making it a convenient option for patients requiring antipsychotic therapy.