Quetiapine 50mg XR Dosing Regimen
Quetiapine XR 50mg should be administered once daily in the evening, typically 1-2 hours before bedtime, with or without food. 1
General Dosing Information
Quetiapine extended-release (XR) formulation is designed for once-daily administration, which differs from the immediate-release (IR) formulation that typically requires twice or three times daily dosing. The XR formulation provides several advantages:
- Improved adherence with once-daily dosing
- More consistent plasma levels throughout the 24-hour period
- Potentially reduced daytime sedation
Administration Guidelines
- Take consistently with or without food (high-fat meals can increase absorption)
- Swallow tablets whole; do not crush, chew, or split XR tablets
- Evening administration (typically 1-2 hours before bedtime) helps minimize daytime sedation
Dosing by Indication
Bipolar Depression
- Starting dose: 50mg once daily in the evening
- Target dose: 300mg once daily by day 4
- Titration schedule:
- Day 1: 50mg once daily
- Day 2: 100mg once daily
- Day 3: 200mg once daily
- Day 4: 300mg once daily
Schizophrenia
- Starting dose: 300mg once daily in the evening
- Effective dose range: 400-800mg once daily
- Maximum recommended dose: 800mg daily
Major Depressive Disorder (Adjunctive Therapy)
- Starting dose: 50mg once daily in the evening
- Target dose: 150-300mg once daily
- Titration schedule:
- Day 1-2: 50mg once daily
- Day 3-4: 150mg once daily
- Further adjustments based on response
Special Populations
Elderly Patients
- Starting dose: 50mg once daily
- Slower titration recommended (increase by 50mg/day)
- Lower target doses may be effective
- The American Geriatrics Society recommends lower initial doses (12.5-25mg twice daily) for elderly patients with agitation 1
Hepatic Impairment
- Start at 50mg once daily
- Increase by 50mg daily until effective dose reached
- Lower target doses typically needed
- Close monitoring for side effects
Monitoring Recommendations
- Baseline and periodic monitoring of:
- Blood pressure and heart rate
- Weight and metabolic parameters (glucose, lipids)
- Complete blood count
- Liver function tests
- ECG in high-risk patients (QTc prolongation risk)
Common Side Effects
The most frequent adverse events with quetiapine XR include:
- Dry mouth
- Sedation and somnolence
- Dizziness
- Constipation
- Increased appetite and weight gain 2
Important Considerations
- Quetiapine carries an FDA black box warning regarding increased mortality risk in elderly patients with dementia-related psychosis 1
- Extrapyramidal symptoms are rare with quetiapine compared to other antipsychotics 3
- Plasma prolactin levels typically remain within normal range at all doses 3
- The therapeutic effect may take 1-2 weeks to become apparent
- Abrupt discontinuation should be avoided; gradual dose reduction is recommended
Pitfalls to Avoid
- Administering in the morning, which may increase daytime sedation
- Crushing or splitting XR tablets, which destroys the extended-release mechanism
- Rapid dose escalation in elderly patients or those with hepatic impairment
- Combining with other CNS depressants without appropriate dose adjustments
- Failure to monitor for metabolic side effects
Research has demonstrated that quetiapine XR is effective as a once-daily formulation, providing similar efficacy to multiple daily doses of immediate-release formulations 4, 5.