Seroquel (Quetiapine) Adult Dosing
For schizophrenia in adults, start Seroquel at 25 mg twice daily and titrate to a target dose of 150-750 mg/day (maximum 750 mg/day); for bipolar mania, start at 50 mg twice daily and titrate to 400-800 mg/day (maximum 800 mg/day); for bipolar depression, start at 50 mg once daily at bedtime and titrate to 300 mg/day. 1
Schizophrenia Dosing
Initial titration schedule 1:
- Day 1: 25 mg twice daily (50 mg total)
- Day 2: Increase by 25-50 mg increments to 100 mg total
- Day 3: 200 mg total
- Day 4: 300-400 mg total
- Further adjustments in 25-50 mg twice daily increments, with at least 2 days between changes
Target dose range: 150-750 mg/day divided 2-3 times daily 1
Maximum dose: 750 mg/day 1
The FDA label establishes these parameters clearly, though clinical practice data shows many patients receive higher doses (mean 620 mg/day in state hospitals, with 33.6% receiving >750 mg/day) 2. However, fixed-dose efficacy studies demonstrate that 150-450 mg/day is as effective as 600-750 mg/day 3, 4, and robust controlled data do not support routine use above the licensed range 4.
Bipolar Disorder Dosing
Acute Mania (Monotherapy or Adjunct to Lithium/Divalproex)
Rapid titration schedule 1:
- Day 1: 100 mg total (50 mg twice daily)
- Day 2: 200 mg total
- Day 3: 300 mg total
- Day 4: 400 mg total
- Further increases up to 800 mg/day by Day 6 in increments ≤200 mg/day
Target dose: 400-800 mg/day 1
Maximum dose: 800 mg/day 1
Quetiapine is FDA-approved for acute mania in adults and is recognized as a first-line option alongside lithium, valproate, and other atypical antipsychotics 5.
Bipolar Depression
Once-daily bedtime dosing 1:
- Day 1: 50 mg at bedtime
- Day 2: 100 mg
- Day 3: 200 mg
- Day 4: 300 mg (target dose)
Target and maximum dose: 300 mg/day at bedtime 1
This is the only FDA-approved indication for quetiapine as monotherapy for bipolar depression in adults 1.
Maintenance Treatment (Bipolar I Disorder)
Dose: 400-800 mg/day divided twice daily as adjunct to lithium or divalproex 1
Patients generally continue on the same dose they were stabilized on during acute treatment. Quetiapine is not FDA-approved as monotherapy for bipolar maintenance 1.
Special Populations
Elderly Patients
- Start at 50 mg/day 1
- Increase in 50 mg/day increments
- Use slower titration and careful monitoring for hypotension 1
The evidence provided shows quetiapine dosing for elderly patients with Alzheimer's disease starts at 12.5 mg twice daily (maximum 200 mg twice daily) 6, but this is for behavioral symptoms in dementia, not schizophrenia or bipolar disorder. Note: Seroquel carries a black box warning for increased mortality in elderly patients with dementia-related psychosis and is not approved for this use 1.
Hepatic Impairment
- Start at 25 mg/day 1
- Increase in 25-50 mg/day increments to effective dose
Drug Interactions
When co-administered with potent CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir, nefazodone):
- Reduce quetiapine dose to one-sixth of original dose 1
- When inhibitor discontinued, increase quetiapine by 6-fold 1
Administration
- Can be taken with or without food 1
- Twice-daily dosing is standard for schizophrenia and mania 7
- Once-daily bedtime dosing for bipolar depression 1
Key Safety Considerations
Monitor for:
- Orthostatic hypotension, especially during initial titration 6
- Metabolic changes (weight gain, hyperglycemia, dyslipidemia) 1
- Sedation (quetiapine is more sedating than other atypicals) 6
- Cataracts (lens examination at baseline and every 6 months) 1
Adequate therapeutic trial: 4-6 weeks at therapeutic dose before considering switch 8, 9