Comparative Pharmacology
Head-to-head clinical analysis: SEROQUEL versus SEROQUEL XR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SEROQUEL versus SEROQUEL XR.
SEROQUEL vs SEROQUEL XR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antagonist at dopamine D2 and serotonin 5-HT2A receptors; also blocks histamine H1 and adrenergic α1 receptors.
SEROQUEL XR (quetiapine fumarate) is an atypical antipsychotic that acts as an antagonist at multiple neurotransmitter receptors: serotonin 5-HT1A and 5-HT2A, dopamine D1 and D2, histamine H1, and adrenergic α1 and α2 receptors. It also has partial agonist activity at 5-HT1A receptors. The therapeutic efficacy in schizophrenia and bipolar disorder is primarily attributed to dopamine D2 and serotonin 5-HT2A antagonism.
Initial: 25 mg twice daily; titrate by 25-50 mg twice daily on day 2 and 3 to target 300-400 mg daily in 2-3 divided doses. Maintenance: 400-800 mg daily. Maximum: 800 mg daily.
Initial: 300 mg orally once daily; may increase by 300 mg/day every 2-3 days. Target dose: 400-800 mg/day for schizophrenia; 300-600 mg/day for bipolar depression; 400-800 mg/day for acute mania. Maximum: 800 mg/day.
None Documented
None Documented
Terminal elimination half-life approximately 7 hours for quetiapine; for metabolite N-desalkylquetiapine (norquetiapine), approximately 12 hours. Steady-state reached within 2 days.
Terminal elimination half-life: approximately 7 hours (range 6-9 hours) for the extended-release formulation. Clinical context: once-daily dosing achieves steady-state within 2 days.
Primarily hepatic metabolism; <1% excreted unchanged renally. Metabolites excreted in urine (73%) and feces (20%).
Primarily hepatic; 70-73% excreted in urine as metabolites (mostly inactive), 20-24% in feces. Less than 1% excreted unchanged in urine.
Category C
Category C
Atypical Antipsychotic
Atypical Antipsychotic