Comparative Pharmacology
Head-to-head clinical analysis: CLOZARIL versus QUETIAPINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CLOZARIL versus QUETIAPINE.
CLOZARIL vs Quetiapine
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Clozapine is an atypical antipsychotic that binds to multiple receptors including dopamine D1-D5 (with greater affinity for D4), serotonin 5-HT2A, 5-HT2C, 5-HT3, 5-HT6, 5-HT7, histamine H1, muscarinic M1-M5, and adrenergic α1- and α2-receptors. Its therapeutic efficacy is primarily attributed to antagonism of D2 and 5-HT2A receptors. It also has weak D2 antagonism and rapid dissociation from D2 receptors, which may contribute to lower extrapyramidal side effects.
Antagonist at serotonin 5-HT2A, dopamine D2, histamine H1, and adrenergic α1 receptors; weak partial agonist at 5-HT1A and serotonin transporter.
Initial 12.5 mg orally once or twice daily, titrate by 25-50 mg/day over 2 weeks to target 300-450 mg/day in divided doses; max 900 mg/day.
Initial: 25 mg PO BID, titrate to effective range 150-750 mg/day divided BID-TID; schizophrenia: 150-750 mg/day, bipolar disorder: 400-800 mg/day, major depressive disorder (adjunct): 150-300 mg/day at bedtime.
None Documented
None Documented
Clinical Note
moderateQuetiapine + Levofloxacin
"Quetiapine may increase the QTc-prolonging activities of Levofloxacin."
Clinical Note
moderateQuetiapine + Norfloxacin
"Quetiapine may increase the QTc-prolonging activities of Norfloxacin."
Clinical Note
moderateQuetiapine + Gemifloxacin
"Quetiapine may increase the QTc-prolonging activities of Gemifloxacin."
Clinical Note
moderateQuetiapine + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Quetiapine is combined with Fluticasone propionate."
Terminal elimination half-life is approximately 8–12 hours at steady state; range 6–26 hours, increasing with dose due to saturable metabolism.
Terminal elimination half-life: ~6-7 hours (parent drug); extended-release: ~7 hours. Clinically, dosing is twice daily for immediate-release; once daily for extended-release.
Approximately 50% excreted renally as metabolites, with less than 1% unchanged; 30% eliminated in feces via biliary excretion.
Renal: 73% (as metabolites), Fecal: 20% (as metabolites), unchanged drug: <1% renal
Category C
Category C
Atypical Antipsychotic
Atypical Antipsychotic