New atypical antipsychotics for schizophrenia: iloperidone

Area of Science:

• Psychiatry
• Pharmacology
• Clinical Trials

Background:

• Schizophrenia treatment faces challenges with existing antipsychotics, including compliance issues and side effects.
• Iloperidone, a novel dopamine D(2)/serotonin 5-HT(2A) antagonist, was developed to improve efficacy and tolerability.
• Its structural similarity to risperidone suggests potential for reduced extrapyramidal symptoms.

Purpose of the Study:

• To evaluate the efficacy and safety of iloperidone in treating schizophrenia.
• To compare iloperidone's effectiveness against placebo, haloperidol, and risperidone.
• To assess the long-term outcomes and adverse event profile of iloperidone.

Main Methods:

• Double-blind, Phase III clinical trials were conducted.
• Oral doses of iloperidone ranging from 12 to 24 mg were administered.
• Efficacy was measured using the Positive and Negative Syndrome Scale (PANSS) and Brief Psychiatric Rating Scale (BPRS).
• Safety and tolerability were monitored, including extrapyramidal symptoms, metabolic changes, and QTc interval.

Main Results:

• Iloperidone significantly reduced schizophrenia symptoms compared to placebo.
• Efficacy was comparable to haloperidol and risperidone in post-hoc analyses.
• Long-term efficacy was equivalent to haloperidol.
• Common adverse events included dizziness, dry mouth, dyspepsia, and somnolence.
• Few extrapyramidal symptoms and metabolic changes were observed.
• QTc interval prolongation was noted, comparable to haloperidol and ziprasidone.

Conclusions:

• Iloperidone demonstrates efficacy in treating schizophrenia symptoms.
• The drug is generally well-tolerated with a low incidence of extrapyramidal symptoms and metabolic changes.
• Concerns regarding QTc interval prolongation necessitate further comparative studies.
• The benefit/risk profile and optimal role of iloperidone in schizophrenia treatment require additional research.