Quetiapine (Seroquel) Dosage and Usage for Schizophrenia and Bipolar Disorder
For treating schizophrenia and bipolar disorder, quetiapine should be initiated at low doses (25-50 mg/day) and gradually titrated to therapeutic doses of 300-800 mg/day for schizophrenia and 300-600 mg/day for bipolar depression, administered in divided doses.
Dosing for Schizophrenia
Initial Dosing and Titration
- Start with 25-50 mg/day and increase gradually to target dose 1, 2
- Titrate to 300-400 mg/day by day 4, divided into two daily doses 2
- Further titration based on clinical response and tolerability within 150-750 mg/day range 2
Maintenance Dosing
- Recommended target dosage: 300-450 mg/day administered as 2 doses 2
- For patients not responding to lower doses, consider increasing to 400-800 mg/day 3
- Maximum FDA-approved dose is 800 mg/day, though some treatment-resistant cases may require higher doses under specialist supervision 2, 4
Special Populations
- Elderly patients: Start with 25 mg/day and increase by 25-50 mg daily to an effective dose, which will likely be lower than standard adult dosing 2
- Hepatic impairment: Start with 25 mg/day and titrate slowly 1
- Adolescents (13-17 years): FDA approved for schizophrenia with adjusted dosing due to different pharmacokinetics 1
Dosing for Bipolar Disorder
Bipolar Depression
- Initial dose: 50 mg on day 1, increased to 100 mg on day 2, then 200 mg on day 3, and 300 mg on day 4 1, 5
- Target dose: 300 mg/day (no additional benefit demonstrated with 600 mg/day) 5
- Administer once daily at bedtime 5
Bipolar Mania
- Initial dose: 50 mg twice daily on day 1, increased to 100 mg twice daily on day 2,150 mg twice daily on day 3, and 200 mg twice daily on day 4 6
- Target dose: 400-800 mg/day in divided doses 6, 1
- For children/adolescents (10-17 years): FDA approved with adjusted dosing 1
Administration Considerations
- Immediate-release formulation is typically administered twice daily 2
- Extended-release formulation can be administered once daily, typically at bedtime 5
- Can be taken with or without food 1
- Oral route only for standard treatment of schizophrenia and bipolar disorder 6
Monitoring and Safety
- No routine blood monitoring required (unlike clozapine) 3
- Monitor for sedation, orthostatic hypotension, and dizziness, especially during initial titration 6
- Less likely to cause extrapyramidal symptoms (EPS) than typical antipsychotics 3
- Monitor for metabolic effects including weight gain and changes in blood glucose and lipid parameters 5
- Reduce dose in patients with hepatic impairment 1
Common Side Effects
- Sedation (use caution when driving or operating machinery) 6, 5
- Dry mouth 5
- Dizziness 6
- Orthostatic hypotension, especially during initial titration 6
- Constipation 5
- Weight gain (though less than some other atypical antipsychotics) 5
Clinical Pearls
- Quetiapine has lower risk of extrapyramidal symptoms compared to typical antipsychotics and some atypical antipsychotics 6, 3
- For treatment-resistant schizophrenia, consider clozapine before using quetiapine doses above 800 mg/day 6
- In bipolar depression, quetiapine monotherapy has demonstrated efficacy without increasing risk of switching to mania 5
- Avoid abrupt discontinuation; taper gradually to minimize withdrawal symptoms 5
- Potential for abuse has been reported, particularly in patients with substance use disorders 7