Quetiapine Dosing Recommendations
For schizophrenia in adults, start quetiapine at 25 mg twice daily on day 1, increase to 300-400 mg/day by day 4 in divided doses, with a target range of 150-750 mg/day and maximum of 750 mg/day. 1
Standard Dosing by Indication
Schizophrenia - Adults
- Day 1: 25 mg twice daily 1
- Days 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 (maximum 750 mg/day) 1
- Further adjustments can be made in increments of 25-50 mg twice daily, with intervals of at least 2 days between changes 1
Schizophrenia - Adolescents (13-17 years)
- Day 1: 25 mg twice daily 1
- Day 2: 100 mg/day (divided twice daily) 1
- Day 3: 200 mg/day 1
- Day 4: 300 mg/day 1
- Day 5: 400 mg/day 1
- Target range: 400-800 mg/day (maximum 800 mg/day) 1
- Adjustments should not exceed 100 mg/day increments 1
Bipolar Mania - Adults
- Day 1: 100 mg/day (divided twice daily) 1
- Day 2: 200 mg/day 1
- Day 3: 300 mg/day 1
- Day 4: 400 mg/day 1
- Target range: 400-800 mg/day (maximum 800 mg/day) 1
- Further increases up to 800 mg/day by day 6 should not exceed 200 mg/day increments 1
Bipolar Mania - Children/Adolescents (10-17 years)
- Day 1: 25 mg twice daily 1
- Day 2: 100 mg/day 1
- Day 3: 200 mg/day 1
- Day 4: 300 mg/day 1
- Day 5: 400 mg/day 1
- Target range: 400-600 mg/day (maximum 600 mg/day) 1
Bipolar Depression - Adults
- Administered once daily at bedtime 1
- Day 1: 50 mg 1
- Day 2: 100 mg 1
- Day 3: 200 mg 1
- Day 4: 300 mg 1
- Target dose: 300 mg/day (maximum 300 mg/day) 1
Special Population Dosing
Elderly Patients
- Start at 50 mg/day 1
- Increase in 50 mg/day increments based on clinical response and tolerability 1
- Use a slower titration rate and lower target dose due to increased risk of hypotensive reactions 1
Hepatic Impairment
Acute Delirium Settings
- For immediate-release formulation in acute settings, start with 25 mg orally stat, with scheduled dosing every 12 hours if needed 2
Critical Safety Monitoring
Orthostatic Hypotension
- Monitor orthostatic vital signs during initial dose titration, particularly in elderly patients and those on concurrent CNS depressants 3, 2
- This is the most important safety concern during titration, as quetiapine causes sedation and orthostatic hypotension 3
Metabolic Parameters
- Monitor weight, fasting glucose, and lipids, as quetiapine affects metabolism 4
- Weight gain of approximately 2.1 kg occurs in short-term trials 5
Hepatic Function
- Monitor for asymptomatic, generally transient elevations in hepatic transaminases (particularly alanine aminotransferase) 5
Thyroid Function
- Small dose-related decreases in total and free thyroxine may occur, which usually reverse with treatment cessation 5
Administration Considerations
Dosing Frequency
- Twice-daily administration is as effective as three-times-daily dosing for the same total daily dose 5
- Quetiapine can be taken with or without food 1
Discontinuation
- Avoid abrupt discontinuation, as this can cause rebound insomnia, agitation, and symptom relapse 4, 2
Common Pitfalls to Avoid
- Do not titrate too rapidly in elderly or debilitated patients, as they require slower titration and lower target doses 1
- Do not exceed maximum recommended doses (750 mg/day for schizophrenia in adults, 800 mg/day for bipolar mania) without clear clinical justification, as efficacy data beyond these doses are limited 1, 6
- Do not add stimulants for quetiapine-induced sedation; instead, adjust the dose schedule to minimize daytime tiredness 4
Evidence on Dose-Response Relationship
Fixed-dose studies demonstrate that quetiapine 150-450 mg/day is more effective than placebo and no less effective than 600-750 mg/day for schizophrenia 6. The standard dosage range is appropriate for clinical use, with robust controlled data not supporting the routine use of higher dosages for full therapeutic effect 6.