Comparative Pharmacology
Head-to-head clinical analysis: QUETIAPINE FUMARATE versus SEROQUEL XR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: QUETIAPINE FUMARATE versus SEROQUEL XR.
QUETIAPINE FUMARATE vs SEROQUEL XR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antagonist at serotonin 5-HT2A, dopamine D2, histamine H1, alpha1-adrenergic, and muscarinic M1 receptors. Also partial agonist at serotonin 5-HT1A and dopamine D2 receptors (depending on dose).
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.
Immediate release: 25-100 mg orally twice daily, titrated as needed up to 400-800 mg/day divided twice daily. Extended release: 50-200 mg orally once daily, titrated up to 400-800 mg/day once 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 is approximately 6-7 hours (quetiapine) and 9-12 hours for the active metabolite norquetiapine; with extended-release formulation, effective half-life is ~7 hours due to slower absorption. Clinical steady-state achieved 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.
Renal: 73% (20% unchanged, remainder as metabolites); Fecal: 21%; Approximately 5% excreted in feces as unchanged drug.
Primarily hepatic; 70-73% excreted in urine as metabolites (mostly inactive), 20-24% in feces. Less than 1% excreted unchanged in urine.
Category A/B
Category C
Atypical Antipsychotic
Atypical Antipsychotic