What is the typical dosing for Seroquel (quetiapine) ER?

Seroquel ER Dosing

For Seroquel XR (extended-release quetiapine), initiate at 300 mg once daily on day 1, increase to 600 mg on day 2, and target 400-800 mg once daily thereafter, with dose adjustments based on clinical response and tolerability. 1, 2

Standard Dosing by Formulation

Extended-Release (XR) Formulation

• Rapid titration schedule: 300 mg once daily on day 1, then 600 mg on day 2, with maintenance dosing of 400-800 mg once daily starting day 3 2
• The XR formulation offers the convenience of once-daily dosing, which may improve adherence compared to immediate-release formulations 2
• Maximum dose is 800 mg/day for schizophrenia 1

Immediate-Release (IR) Formulation

• Standard titration for schizophrenia: Day 1: 25 mg twice daily, Day 2: 50-100 mg total (divided doses), Day 3: 200 mg total, Day 4: 300-400 mg total 1
• Target dose range: 150-750 mg/day divided into 2-3 doses, with maximum of 750 mg/day 1, 3
• Both twice-daily and three-times-daily dosing regimens are equally effective at 450 mg/day total 4

Indication-Specific Dosing

Schizophrenia (Adults)

• Target dose: 400-800 mg/day for maintenance 1
• Effective doses typically ≥250 mg/day, with maximum efficacy at higher doses within the therapeutic range 5

Bipolar Depression

• Administer once daily at bedtime: Day 1: 50 mg, Day 2: 100 mg, Day 3: 200 mg, Day 4: 300 mg 1
• Target and maximum dose: 300 mg/day 1, 6

Bipolar Mania (Adults)

• Day 1: 100 mg total (divided), Day 2: 200 mg, Day 3: 300 mg, Day 4: 400 mg 1
• Target range: 400-800 mg/day, maximum 800 mg/day 1

Special Population Adjustments

Elderly Patients

• Start at 50 mg/day with 50 mg/day incremental increases 1
• Maximum dose for Alzheimer's-related behavioral disturbances: 400 mg/day total (200 mg twice daily), starting at 12.5 mg twice daily 3, 7
• Critical warning: Do not use schizophrenia maximum doses (750-800 mg/day) in elderly patients with dementia 3
• Monitor orthostatic hypotension vigilantly during titration 3, 7

Hepatic Impairment

• Start at 25 mg/day with 25-50 mg/day incremental increases 1

Drug Interactions

• With CYP3A4 inhibitors (ketoconazole, ritonavir): Reduce dose to one-sixth of original dose 1
• With CYP3A4 inducers (phenytoin, carbamazepine): Increase dose up to 5-fold of original dose when used chronically (>7-14 days) 1

Critical Safety Monitoring

During Initial Titration

• Monitor orthostatic vital signs, especially in elderly patients and those on CNS depressants 3, 7
• Assess for excessive sedation, which is more prominent with quetiapine than other atypical antipsychotics 3

Discontinuation

• Taper gradually over 10-14 days when discontinuing—avoid abrupt cessation to prevent rebound insomnia, agitation, and symptom relapse 3, 8
• Withdrawal symptoms can occur with rapid dose decreases 3

Common Pitfalls to Avoid

• Do not exceed 6 mg daily of risperidone when cross-titrating (note: this applies to switching scenarios, not quetiapine monotherapy) 8
• Do not use maximum schizophrenia doses in elderly dementia patients—the ceiling is 400 mg/day, not 750-800 mg/day 3
• Quetiapine does not cause sustained prolactin elevation, distinguishing it from many other antipsychotics 4, 5
• The relatively short 6-hour half-life does not predict dosing frequency; twice-daily dosing is adequate for immediate-release formulations 4, 5

Reinitiation After Treatment Gap

• If quetiapine has been discontinued for more than one week, restart using the initial titration schedule rather than resuming the previous maintenance dose 1