Comparative Pharmacology
Head-to-head clinical analysis: GEODON versus RISPERDAL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GEODON versus RISPERDAL.
GEODON vs RISPERDAL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Ziprasidone is an atypical antipsychotic with high affinity for dopamine D2 and serotonin 5-HT2A receptors; it also antagonizes 5-HT2C, 5-HT1D, alpha1-adrenergic, and histamine H1 receptors, and moderately inhibits serotonin and norepinephrine reuptake.
Risperidone is a benzisoxazole atypical antipsychotic that antagonizes dopamine D2 and serotonin 5-HT2A receptors. It also blocks alpha1-adrenergic, alpha2-adrenergic, and histamine H1 receptors.
20 mg orally twice daily with food; may titrate to 40-80 mg orally twice daily; maximum 80 mg orally twice daily. For acute treatment, IM 10-20 mg as needed up to 40 mg/day.
2-8 mg orally once daily or divided twice daily; maximum 16 mg/day
None Documented
None Documented
Terminal elimination half-life is approximately 7 hours (range 5-10 hours) for oral ziprasidone; after intramuscular administration, half-life is about 2-5 hours. This short half-life may require twice-daily dosing for oral therapy.
20 hours (parent drug), 23 hours (active metabolite 9-hydroxyrisperidone). Steady state reached in 5-6 days. Extended in elderly and hepatic/renal impairment.
Primarily hepatic metabolism via aldehyde oxidase and CYP3A4. Approximately 20% excreted renally as unchanged drug, with the remainder as metabolites (mostly fecal).
Renal: 70% (30% as unchanged drug, 40% as metabolites), Fecal/Biliary: 14%
Category C
Category C
Atypical Antipsychotic
Atypical Antipsychotic