Comparative Pharmacology
Head-to-head clinical analysis: CLOZAPINE versus SEROQUEL XR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CLOZAPINE versus SEROQUEL XR.
CLOZAPINE vs SEROQUEL XR
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.
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: 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.
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
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: approximately 7 hours (range 6-9 hours) for the extended-release formulation. Clinical context: once-daily dosing achieves steady-state within 2 days.
Approximately 50% of the dose is excreted in urine (30% as unchanged drug and metabolites) and 30% in feces via biliary elimination.
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
"The risk or severity of adverse effects can be increased when Clozapine is combined with Furosemide."