What is the typical dose and frequency of Seroquel (quetiapine) for schizophrenia and bipolar disorder?

Quetiapine (Seroquel) Dosing for Schizophrenia and Bipolar Disorder

For schizophrenia, the recommended dose of quetiapine is 300-750 mg/day for adults, typically given in divided doses twice daily, while for bipolar disorder, the recommended dose is 400-800 mg/day for mania and 300 mg/day for bipolar depression. 1

Schizophrenia Dosing

Adults with Schizophrenia

• Initial titration:
  • Day 1: 25 mg twice daily
  • Days 2-3: Increase in increments of 25-50 mg divided two or three times daily
  • Day 4: Target range of 300-400 mg/day
  • Further adjustments can be made in increments of 25-50 mg twice daily, at intervals of not less than 2 days
• Recommended maintenance dose: 150-750 mg/day
• Maximum dose: 750 mg/day 1

Adolescents with Schizophrenia (13-17 years)

• Initial titration:
  • Day 1: 25 mg twice daily
  • Day 2: 100 mg/day (divided twice daily)
  • Day 3: 200 mg/day (divided twice daily)
  • Day 4: 300 mg/day (divided twice daily)
  • Day 5: 400 mg/day (divided twice daily)
• Recommended dose: 400-800 mg/day
• Maximum dose: 800 mg/day 1

Bipolar Disorder Dosing

Bipolar Mania - Adults

• Initial titration:
  • Day 1: 100 mg/day (divided twice daily)
  • Day 2: 200 mg/day (divided twice daily)
  • Day 3: 300 mg/day (divided twice daily)
  • Day 4: 400 mg/day (divided twice daily)
  • Further adjustments up to 800 mg/day by Day 6 in increments of no greater than 200 mg/day
• Recommended dose: 400-800 mg/day
• Maximum dose: 800 mg/day 1

Bipolar Mania - Children and Adolescents (10-17 years)

• Initial titration:
  • Day 1: 25 mg twice daily
  • Day 2: 100 mg/day (divided twice daily)
  • Day 3: 200 mg/day (divided twice daily)
  • Day 4: 300 mg/day (divided twice daily)
  • Day 5: 400 mg/day (divided twice daily)
• Recommended dose: 400-600 mg/day
• Maximum dose: 600 mg/day 1

Bipolar Depression - Adults

• Initial titration (once daily at bedtime):
  • Day 1: 50 mg
  • Day 2: 100 mg
  • Day 3: 200 mg
  • Day 4: 300 mg
• Recommended dose: 300 mg/day
• Maximum dose: 300 mg/day 1

Bipolar I Disorder Maintenance - Adults

• Recommended dose: 400-800 mg/day (divided twice daily) as adjunct to lithium or divalproex
• Maximum dose: 800 mg/day 1

Administration Considerations

Dosing Frequency

• Quetiapine can be administered twice daily for most indications
• Clinical trials have shown that twice-daily (BD) dosing is as effective as three-times-daily (TID) dosing 2
• Bipolar depression is the only indication specifically requiring once-daily dosing at bedtime 1

Special Populations

Elderly Patients

• Start with 50 mg/day
• Increase in increments of 50 mg/day depending on clinical response and tolerability 1

Hepatically Impaired Patients

• Start with 25 mg/day
• Increase daily in increments of 25-50 mg/day to an effective dose 1

When Used with CYP3A4 Inhibitors

• Reduce dose to one-sixth of original dose 1

When Used with CYP3A4 Inducers

• Increase dose up to 5-fold of original dose 1

Clinical Pearls and Caveats

1. Dose-Response Relationship:

   • For schizophrenia, doses of 150-450 mg/day have been shown to be effective and no less effective than higher doses in some studies 3
   • Extended-release formulation studies suggest 600-800 mg/day may be more effective than 400 mg/day 4

2. Monitoring Requirements:

   • Monitor for common side effects: headache, somnolence, dizziness, postural hypotension, and dry mouth 5
   • Watch for transient liver enzyme elevations, which are generally asymptomatic 5
   • Monitor thyroid function as quetiapine can cause small dose-related decreases in thyroid hormone levels 5

3. Advantages Over Typical Antipsychotics:

   • Lower risk of extrapyramidal symptoms compared to haloperidol and chlorpromazine 5
   • Does not typically elevate prolactin levels 5

4. Low-Dose Applications:

   • Low doses (25-75 mg/day) may be useful for impulse control in bipolar disorder patients in remission 6, though this is outside the FDA-approved dosing range

5. Administration Flexibility:

   • Can be taken with or without food 1
   • Extended-release formulation allows for once-daily dosing, which may improve adherence 4

Remember that while these are the recommended doses, clinical response and tolerability should guide individual dosing decisions, with careful monitoring for efficacy and side effects.