Comparative Pharmacology
Head-to-head clinical analysis: CLOZAPINE versus ZYPREXA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CLOZAPINE versus ZYPREXA.
CLOZAPINE vs ZYPREXA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Atypical antipsychotic; binds to dopamine D4, serotonin 5-HT2A, and adrenergic α2 receptors; weak D2 antagonist with rapid dissociation; also affects histaminergic and cholinergic receptors.
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: 12.5 mg orally once or twice daily; titrate gradually by 25-50 mg/day to target dose 300-450 mg/day in divided doses; max 900 mg/day.
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
moderateClozapine + Norfloxacin
"Clozapine may increase the QTc-prolonging activities of Norfloxacin."
Clinical Note
moderateClozapine + Torasemide
"The risk or severity of adverse effects can be increased when Clozapine is combined with Torasemide."
Clinical Note
moderateClozapine + Etacrynic acid
"The risk or severity of adverse effects can be increased when Clozapine is combined with Etacrynic acid."
Clinical Note
moderateClozapine + Furosemide
Terminal elimination half-life is 8 to 12 hours (steady-state), but can range from 4 to 66 hours; requires dose adjustment in renal/hepatic impairment.
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.
Approximately 50% of the dose is excreted in urine (30% as unchanged drug and metabolites) and 30% in feces via biliary elimination.
Primarily hepatic metabolism via CYP1A2 and CYP2D6; ~7% excreted unchanged in urine, ~57% in urine as metabolites, ~30% in feces (mostly metabolites).
Category A/B
Category C
Atypical Antipsychotic
Atypical Antipsychotic
"The risk or severity of adverse effects can be increased when Clozapine is combined with Furosemide."