Comparative Pharmacology
Head-to-head clinical analysis: QUETIAPINE versus ZYPREXA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: QUETIAPINE versus ZYPREXA.
Quetiapine vs ZYPREXA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antagonist at serotonin 5-HT2A, dopamine D2, histamine H1, and adrenergic α1 receptors; weak partial agonist at 5-HT1A and serotonin transporter.
Olanzapine is an atypical antipsychotic that antagonizes dopamine D2 and serotonin 5-HT2A receptors, with higher affinity for 5-HT2A than D2. It also blocks histamine H1, alpha-1 adrenergic, and muscarinic M1 receptors.
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.
5-10 mg orally once daily; may increase by 5 mg/day at intervals of at least 1 week; maximum 20 mg/day.
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: ~6-7 hours (parent drug); extended-release: ~7 hours. Clinically, dosing is twice daily for immediate-release; once daily for extended-release.
Terminal elimination half-life ~30 hours (range 21–54 h) in adults, allowing once-daily dosing; steady-state reached in ~5–7 days. Half-life prolonged in elderly, females, and hepatic impairment.
Renal: 73% (as metabolites), Fecal: 20% (as metabolites), unchanged drug: <1% renal
Primarily hepatic metabolism via CYP1A2 and CYP2D6; ~7% excreted unchanged in urine, ~57% in urine as metabolites, ~30% in feces (mostly metabolites).
Category C
Category C
Atypical Antipsychotic
Atypical Antipsychotic