Seroquel (Quetiapine) Dosing Recommendations
Schizophrenia
For adults with schizophrenia, start quetiapine at 25 mg twice daily on Day 1, increase to 300-400 mg/day by Day 4, with a recommended maintenance dose of 150-750 mg/day (maximum 750 mg/day). 1
Adult Dosing Algorithm
- Day 1: 25 mg twice daily 1
- Day 2-3: Increase in increments of 25-50 mg divided 2-3 times daily 1
- Day 4: Target 300-400 mg/day 1
- Maintenance: 150-750 mg/day, with further adjustments in increments of 25-50 mg twice daily at intervals of at least 2 days 1
- Maximum dose: 750 mg/day 1
Adolescent Dosing (13-17 years)
- Day 1: 25 mg twice daily 1
- Day 2: 100 mg/day (divided twice daily) 1
- Day 3: 200 mg/day (divided twice daily) 1
- Day 4: 300 mg/day (divided twice daily) 1
- Day 5: 400 mg/day (divided twice daily) 1
- Maintenance: 400-800 mg/day, with adjustments no greater than 100 mg/day 1
- Maximum dose: 800 mg/day 1
Evidence for Efficacy
- Quetiapine 300 mg/day demonstrated therapeutic equivalence with haloperidol 12 mg/day in schizophrenia 2
- Maximum clinical effects occur at dosages ≥250 mg/day 2
- Studies consistently found quetiapine effective at approximately 600 mg/day for acute exacerbation of schizophrenia 3
- Twice-daily dosing (225 mg bid) is as effective as three-times-daily dosing (150 mg tid) for a total of 450 mg/day 4
Bipolar Disorder
Bipolar Mania (Adults)
For acute mania in adults, start quetiapine at 100 mg/day (divided twice daily) on Day 1, increase to 400 mg/day by Day 4, with a recommended dose of 400-800 mg/day (maximum 800 mg/day). 1
- Day 1: 100 mg/day (divided twice daily) 1
- Day 2: 200 mg/day (divided twice daily) 1
- Day 3: 300 mg/day (divided twice daily) 1
- Day 4: 400 mg/day (divided twice daily) 1
- Further adjustments: Up to 800 mg/day by Day 6 in increments no greater than 200 mg/day 1
- Maintenance: 400-800 mg/day 1
Bipolar Mania (Children and Adolescents, 10-17 years)
- Day 1: 25 mg twice daily 1
- Day 2: 100 mg/day (divided twice daily) 1
- Day 3: 200 mg/day (divided twice daily) 1
- Day 4: 300 mg/day (divided twice daily) 1
- Day 5: 400 mg/day (divided twice daily) 1
- Maintenance: 400-600 mg/day, with adjustments no greater than 100 mg/day 1
- Maximum dose: 600 mg/day 1
Bipolar Depression (Adults)
For bipolar depression in adults, start quetiapine at 50 mg once daily at bedtime on Day 1, increase to 300 mg/day by Day 4 (maximum 300 mg/day). 1
- Day 1: 50 mg once daily at bedtime 1
- Day 2: 100 mg once daily at bedtime 1
- Day 3: 200 mg once daily at bedtime 1
- Day 4: 300 mg once daily at bedtime 1
- Maintenance: 300 mg/day 1
Evidence for Bipolar Depression
- Quetiapine 300 mg/day or 600 mg/day produced significantly greater improvements than placebo in depressive symptoms 5
- No differences in treatment outcomes between 300 mg/day and 600 mg/day dosage groups 5
- Studies consistently found quetiapine effective at doses of 150-300 mg/day for unipolar depression and 300-600 mg/day for bipolar depression 3
Bipolar Maintenance Therapy
- Continue the dose that stabilized the acute episode, typically 400-800 mg/day as adjunct to lithium or divalproex 1
- Quetiapine responders who continued therapy had significantly reduced risk of recurrence of any mood events and depression mood events 5
Major Depressive Disorder (Off-Label)
For major depressive disorder, quetiapine is effective at doses of approximately 150-300 mg/day, though this is an off-label use. 3
- Studies consistently found quetiapine effective versus placebo at doses of 150-300 mg/day for unipolar depression 3
Special Populations
Elderly Patients
Start elderly patients on quetiapine 50 mg/day, with dose increases in increments of 50 mg/day depending on clinical response and tolerability. 1
- Use a slower rate of dose titration and lower target dose in elderly patients 1
- Elderly patients have approximately 20-30% higher plasma concentrations and up to 50% lower oral clearance compared to younger patients 2
Hepatic Impairment
Start patients with hepatic impairment on quetiapine 25 mg/day, with daily increases of 25 mg/day to an effective dose. 1
- Mean oral clearance is reduced by approximately 25% in patients with hepatic cirrhosis 2
Renal Impairment
- Mean oral clearance is reduced by approximately 25% in patients with severe renal impairment 2
- Consider dose reduction similar to hepatic impairment 6
Drug Interactions
CYP3A4 Inhibitors
When co-administered with potent CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir), reduce quetiapine dose to one-sixth of the original dose. 1
- When the CYP3A4 inhibitor is discontinued, increase quetiapine dose by 6-fold 1
CYP3A4 Inducers
When used with chronic treatment (>7-14 days) of potent CYP3A4 inducers (phenytoin, carbamazepine, rifampin), increase quetiapine dose up to 5-fold of the original dose. 1
- When the CYP3A4 inducer is discontinued, reduce quetiapine dose to the original level within 7-14 days 1
Reinitiation After Discontinuation
For patients off quetiapine for more than one week, follow the initial dosing schedule when restarting. 1
- For patients off quetiapine for less than one week, gradual dose escalation may not be required and the maintenance dose may be reinitiated 1
Common Pitfalls to Avoid
- Underdosing in schizophrenia: Maximum effects occur at dosages ≥250 mg/day, so doses below this threshold may be inadequate 2
- Rapid titration: Increases should occur at intervals of at least 2 days to minimize adverse effects 1
- Ignoring drug interactions: Failure to adjust dose with CYP3A4 inhibitors or inducers can lead to toxicity or treatment failure 1
- Inadequate trial duration: Allow 4-6 weeks at therapeutic doses before concluding ineffectiveness 7
- Premature discontinuation in bipolar disorder: Maintenance therapy should continue for at least 12-24 months after stabilization 7
Tolerability Considerations
- Most common adverse events include dry mouth, sedation, somnolence, dizziness, and constipation 5
- Quetiapine has a low propensity for extrapyramidal symptoms across all doses 2, 4
- Weight gain of approximately 2.1 kg occurs in short-term trials 2
- Even low doses may lead to increases in weight and triglycerides across psychiatric disorders 3
- Quetiapine is not associated with sustained increases in plasma prolactin 2, 4
- Asymptomatic, transient elevations in hepatic transaminases may occur 2
- Small dose-related decreases in total and free thyroxine occur, usually reversing with treatment cessation 2