Seroquel (Quetiapine) Dosing Recommendations
For schizophrenia in adults, start quetiapine at 25 mg twice daily on day 1, titrate to 300-400 mg/day by day 4, with a therapeutic range of 150-750 mg/day and a maximum dose of 750 mg/day. 1
Dosing by Indication
Schizophrenia - Adults
- Initial titration: Day 1: 25 mg twice daily; Days 2-3: increase by 25-50 mg divided 2-3 times daily to reach 300-400 mg by day 4 1
- Therapeutic range: 150-750 mg/day 1
- Maximum dose: 750 mg/day 2, 1
- Further adjustments can be made in increments of 25-50 mg twice daily, with intervals of at least 2 days 1
Schizophrenia - Adolescents (13-17 years)
- Initial titration: Day 1: 25 mg twice daily; Day 2: 100 mg total; Day 3: 200 mg total; Day 4: 300 mg total; Day 5: 400 mg total 1
- Therapeutic range: 400-800 mg/day 1
- Maximum dose: 800 mg/day 1
- Further adjustments should not exceed 100 mg/day increments 1
Bipolar Mania - Adults
- Initial titration: Day 1: 100 mg total; Day 2: 200 mg total; Day 3: 300 mg total; Day 4: 400 mg total 1
- Therapeutic range: 400-800 mg/day 1
- Maximum dose: 800 mg/day 1
- Further adjustments up to 800 mg/day by day 6 should not exceed 200 mg/day increments 1
Bipolar Mania - Children and Adolescents (10-17 years)
- Initial titration: Same as adolescent schizophrenia dosing 1
- Therapeutic range: 400-600 mg/day 1
- Maximum dose: 600 mg/day 1
Bipolar Depression - Adults
- Administer once daily at bedtime: Day 1: 50 mg; Day 2: 100 mg; Day 3: 200 mg; Day 4: 300 mg 1
- Therapeutic and maximum dose: 300 mg/day 1
Bipolar I Maintenance Therapy - Adults
- Dosing: 400-800 mg/day administered twice daily as adjunct to lithium or divalproex 1
- Patients generally continue on the same dose on which they were stabilized 1
Special Population Dosing
Elderly Patients
- Start at 50 mg/day (not the standard 25 mg twice daily) 1
- Increase in increments of 50 mg/day based on clinical response and tolerability 1
- For Alzheimer's disease-related behavioral disturbances: Initial dose of 12.5 mg twice daily, maximum 200 mg twice daily (400 mg/day total) 2, 3, 4
- Critical consideration: Do not use maximum schizophrenia doses (750-800 mg/day) in elderly patients with dementia—the maximum for this population is 400 mg/day 2
Hepatic Impairment
- Start at 25 mg/day 1
- Increase daily in increments of 25-50 mg/day to an effective dose based on clinical response 1
Drug Interactions
- With CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir): Reduce quetiapine dose to one-sixth of original dose; when inhibitor discontinued, increase back by 6-fold 1
- With CYP3A4 inducers (phenytoin, carbamazepine, rifampin): Increase quetiapine dose up to 5-fold of original dose for chronic treatment (>7-14 days); when inducer discontinued, reduce to original level within 7-14 days 1
Administration and Monitoring
Dosing Frequency
- Quetiapine can be administered twice daily for most indications, which has been shown to be as effective as three times daily dosing 5
- Can be taken with or without food 1
Critical Monitoring Parameters
- Monitor for orthostatic hypotension during initial dose titration, especially in elderly patients and those on concurrent CNS depressants 2, 3, 4
- Quetiapine is more sedating than other atypical antipsychotics, which may limit tolerability at higher doses 2
Common Pitfalls to Avoid
Discontinuation
- Avoid abrupt discontinuation or rapid dose decreases—withdrawal symptoms can occur 2
- Taper gradually over 10-14 days when discontinuing 2
Reinitiation After Treatment Gap
- If patient has been off quetiapine for more than one week, follow the initial dosing schedule when restarting 1
Dose-Response Considerations
- Fixed-dose studies demonstrate that dosages of 150-450 mg/day are effective and no less effective than 600-750 mg/day 6
- The balance of evidence does not support routine use of dosages above 800 mg/day, despite some case reports suggesting benefit at higher doses 6
- Clinical efficacy is generally dose-related, with maximum effects occurring at dosages ≥250 mg/day 7