Risperidone

Brand Names: Risperidone

Drug Class: Atypical Antipsychotic

Overview

11 DESCRIPTION Risperidone tablets, USP contain risperidone USP, an atypical antipsychotic belonging to the chemical class of benzisoxazole derivatives. The chemical designation is 3-[2-[4-(6-fluoro-1,2- benzisoxazol-3-yl)-1-piperidinyl]ethyl]-6,7,8,9-tetrahydro-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one. Its molecular formula is C 23 H 27 FN 4 O 2 and its molecular weight is 410.49.

Mechanism of Action

12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The mechanism of action of risperidone in schizophrenia is unclear. The drug's therapeutic activity in schizophrenia could be mediated through a combination of dopamine Type 2 (D 2 ) and serotonin Type 2 (5HT 2 ) receptor antagonism. The clinical effect from risperidone results from the combined concentrations of risperidone and its major metabolite, 9-hydroxyrisperidone (paliperidone) [see Clinical Pharmacology ( 12.3 )] . Antagonism at receptors other than D 2 and 5HT 2 may explain some of the other effects of risperidone [see Clinical Pharmacology ( 12.1 )] . 12.2 Pharmacodynamics Risperidone is a monoaminergic antagonist with high affinity (Ki of 0.12 to 7.

Indications

  • 1 INDICATIONS AND USAGE Risperidone tablets are an atypical antipsychotic indicated for: Treatment of schizophrenia ( 1.1 ) As monotherapy or adjunctive therapy with lithium or valproate, for the treatment of acute manic or mixed episodes associated with Bipolar I Disorder ( 1.2 ) Treatment of irritability associated with autistic disorder ( 1.3 ) 1.1 Schizophrenia Risperidone tablets are indicated for the treatment of schizophrenia.

Common Doses

  • 2 mg
  • 8 mg
  • 16 mg
  • 0.5 mg

Dosage

2 DOSAGE AND ADMINISTRATION Table 1. Recommended Daily Dosage by Indication Initial Dose Titration (Increments) Target Dose Effective Dose Range Schizophrenia: adults ( 2.1 ) 2 mg 1 to 2 mg 4 to 8 mg 4 to 16 mg Schizophrenia: adolescents ( 2.2 ) 0.5 mg 0.5 to 1 mg 3 mg 1 to 6 mg Bipolar mania: adults ( 2.2 ) 2 to 3 mg 1 mg 1 to 6 mg 1 to 6 mg Bipolar mania: children and adolescents ( 2.2 ) 0.5 mg 0.5 to 1 mg 1 to 2.5 mg 1 to 6 mg Irritability in autistic disorder ( 2.3 ) 0.25 mg Can increase to 0.5 mg by Day 4: (body weight less than 20 kg) 0.

Black Box Warning

WARNING: INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Risperidone tablets are not approved for the treatment of patients with dementia-related psychosis. [see Warnings and Precautions (5.1) ] WARNING: INCREASED MORTALITY IN ELDERLY PATIENTS WITH DEMENTIA-RELATED PSYCHOSIS See full prescribing information for complete boxed warning Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death.

Contraindications

  • 4 CONTRAINDICATIONS Risperidone tablets are contraindicated in patients with a known hypersensitivity to either risperidone or paliperidone, or to any of the excipients in the risperidone tablets formulation. Hypersensitivity reactions, including anaphylactic reactions and angioedema, have been reported in patients treated with risperidone and in patients treated with paliperidone. Paliperidone is a metabolite of risperidone. Known hypersensitivity to risperidone, paliperidone, or to any excipients in risperidone tablets. ( 4 )

Side Effects

  • 6 ADVERSE REACTIONS The following are discussed in more detail in other sections of the labeling: • Increased mortality in elderly patients with dementia-related psychosis [see Boxed Warning and Warnings and Precautions ( 5.1 )] • Cerebrovascular adverse events, including stroke, in elderly patients with dementia-related psychosis [see Warnings and Precautions ( 5.2 )] • Neuroleptic malignant syndrome [see Warnings and Precautions ( 5.3 )] • Tardive dyskinesia [see Warnings and Precautions ( 5.

Interactions

  • 7 DRUG INTERACTIONS Carbamazepine and other enzyme inducers decrease plasma concentrations of risperidone. Increase the risperidone tablets dose up to double the patient’s usual dose. Titrate slowly. ( 7.1 ) Fluoxetine, paroxetine, and other CYP 2D6 enzyme inhibitors increase plasma concentrations of risperidone. Reduce the initial dose. Do not exceed a final dose of 8 mg per day of risperidone tablets. ( 7.1 ) 7.1 Pharmacokinetic-related Interactions The dose of risperidone tablets should be adjusted when used in combination with CYP2D6 enzyme inhibitors (e.g.