What is the recommended dose of Seroquel (Quetiapine) when administered three times a day (tid)?

Seroquel (Quetiapine) Three Times Daily Dosing

For schizophrenia in adults, when administering quetiapine three times daily, the recommended total daily dose is 300-400 mg by Day 4, divided into 2-3 doses, with a maximum of 750 mg/day. 1

Standard TID Dosing Protocol for Schizophrenia

Initial titration schedule for adults:

• Day 1: 25 mg twice daily (total 50 mg/day) 1
• Day 2: Increase by 25-50 mg increments to 75-100 mg/day divided 2-3 times 1
• Day 3: Continue titration to 150-200 mg/day divided 2-3 times 1
• Day 4: Target dose of 300-400 mg/day divided 2-3 times 1

Maintenance dosing when using TID schedule:

• The optimal treatment range is 300-400 mg/day divided into 2-3 oral doses 2
• Further adjustments can be made in increments of 25-50 mg twice daily, with intervals of at least 2 days between changes 1
• Maximum dose is 750 mg/day regardless of dosing frequency 1

Special Population Adjustments

Elderly or debilitated patients:

• Start at 50 mg/day with slower titration 1
• Increase in 50 mg/day increments based on response 1
• Risk of transient orthostatic hypotension requires careful monitoring 3, 4

Hepatically impaired patients:

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

Clinical Context for TID vs BID Dosing

Important consideration: While quetiapine can be administered three times daily, twice-daily dosing is equally effective and preferred for adherence. A controlled trial demonstrated no significant difference in efficacy between BID and TID administration of 450 mg/day total dose 5. The FDA label primarily recommends twice-daily dosing for most indications 1.

When TID dosing may be appropriate:

• Adolescents with schizophrenia (13-17 years) may receive 400-800 mg/day divided into 2-3 doses based on response and tolerability 1
• Patients experiencing breakthrough symptoms between doses on BID regimen 2

Key Safety Monitoring

Common adverse effects requiring monitoring:

• Orthostatic hypotension, especially during initial titration 3, 6
• Somnolence and dizziness (17.5% and 9.6% respectively) 5
• Transient hepatic transaminase elevations 5
• Small dose-related decreases in thyroid hormones (usually reversible) 5

Critical safety advantage: Quetiapine demonstrates placebo-level incidence of extrapyramidal symptoms across the entire dosage range, unlike typical antipsychotics 5, 7. This allows confident dose escalation without increasing EPS risk 7.

Drug Interactions Requiring Dose Modification

With CYP3A4 inhibitors (ketoconazole, ritonavir):

• Reduce quetiapine dose to one-sixth of original 1

With CYP3A4 inducers (phenytoin, carbamazepine, rifampin):

• Increase quetiapine dose up to 5-fold of original when used chronically (>7-14 days) 1, 2

Reinitiation After Treatment Gap

If patient has been off quetiapine for more than one week: Follow the initial dosing titration schedule starting from Day 1 1. Do not resume at previous maintenance dose due to loss of tolerance.