Source: Health Products Regulatory Authority (ZA) Revision Year: 2025 Publisher: Abex Pharmaceutica (Pty) Ltd, Suite C, Rubenstein Ridge, 617 Rubenstein Drive, Moreleta Park, 0181
A 2.6.5 Central nervous system depressants. Miscellaneous structures
Pharmacotherapeutic group: Other antipsychotics
ATC code: N05AX08
Risperidone is an antipsychotic of the benzisoxazole derivatives. It is a selective monoaminergic antagonist. Risperidone has affinity for serotonin-5-HT2, dopamine-D2, H1histamine, alpha1 and alpha2-adrenergic receptors. Risperidone has no affinity for cholinergic receptors. It is a dopamine D2-antagonist.
Risperidone is completely absorbed after oral administration. Peak plasma concentrations are attained within 1 to 2 hours. Food does not affect the absorption of risperidone.
Steady state is reached within 1 day for risperidone in most patients and 4-5 days for 9-hydroxy-risperidone. Risperidone plasma concentration is dose- proportional within the therapeutic dose-range.
Risperidone is bound to albumin and alpha 1-acid glycoprotein. Plasma protein binding of risperidone is 88% and 77% for 9-hydroxy-risperidone. One week after administration, 70% of the dose is excreted in the urine and 14% in the faeces. In the urine, risperidone and 9-hydroxy-risperidone represent 35-45% of the dose.
Risperidone is metabolised by cytochrome CYP2D6 to 9-hydroxy-risperidone which has a similar pharmacological activity to risperidone. Risperidone and 9-hydroxy-risperidone form the active antipsychotic fraction.
After oral administration to psychotic patients, risperidone's half-life is about 3 hours. The elimination half-life of 9-hydroxy-risperidone and the active antipsychotic fraction is 24 hours.
Risperidone showed significantly higher active plasma concentrations and slower elimination in the elderly and in patients with moderately severe renal insufficiency. The plasma concentrations of risperidone were normal in patients with mild to moderate liver insufficiency.
The pharmacokinetics of risperidone, 9-hydroxy-risperidone and the active moiety in children are similar to those in adults.
© All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.