A roadmap to key pharmacologic principles in using antipsychotics: application in clinical practice

Efficacy and safety of aripiprazole in Chinese Han schizophrenia subjects: a randomized, double-blind, active parallel-controlled, multicenter clinical trial

OBJECTIVE

Antipsychotics, such as aripiprazole and risperidone, are often used to treat individuals with schizophrenia. The efficacy as well as safety of aripiprazole in Western populations has been described. The objective of this study is to investigate the efficacy, safety, and tolerability of aripiprazole and risperidone in Chinese Han schizophrenia subjects in mainland China.

METHOD

The 6-week, double-blind, randomized, parallel study was conducted in 5 medical centers in mainland China from November 2007 to March 2011. A total of 279 subjects with a primary DSM-IV diagnosis of schizophrenia were randomly assigned (with a randomization ratio of 1:1) to aripiprazole (n=139) or risperidone (n=140). Efficacy measurements included the Positive and Negative Syndrome Scale (PANSS) total, positive, negative and general psychopathology subscale scores, and Clinical Global Impressions-Severity of Illness (CGI-S), and Improvement scale scores. Extrapyramidal symptoms (EPS), weight gain, serum prolactin level, QTc interval, and self-reported adverse events were also assessed as measures of safety and tolerability.

RESULTS

Both the aripiprazole and risperidone groups showed statistically significant improvement of PANSS total, positive, negative, general psychopathology subscale scores, and CGI-S scores from baseline to the endpoint (all p<0.01). Significant improvement was noted in the first week for both treatment groups. There were no significant differences in efficacy measurements between the two treatment groups. Mean change of PANSS total scores from baseline to the endpoint was -26.8±18.1 for aripiprazole and -30.0±17.7 for risperidone, (p=0.1475). The responder rate was 71% (n=99) and 76% (n=107) for aripiprazole and risperidone, respectively, (p=0.323). The incidences of EPS were similar in the aripiprazole (25%, n=35) and risperidone groups (24%, n=34), respectively (p=0.757). No clinically meaningful effects on QTc interval, QRS duration, or PR interval were observed in either treatment groups. However, the incidence of clinically significant weight gain (p=0.0118) and hyperprolactinemia (p<0.001) in the aripiprazole group was significantly lower than in the risperidone group.

CONCLUSION

The study demonstrated that aripiprazole, as well as risperidone, had rapid and persistent efficacy for psychotic symptoms from the first week of therapy. There may be poor efficacy for aripiprazole compared with risperidone for overall improvement, but there were no significant differences in this study. Aripiprazole showed good tolerability with less weight gain and hyperprolactinemia compared with risperidone. The overall efficacy and safety of aripiprazole in Chinese Han schizophrenia subjects were similar to that reported in Western populations.

Desvenlafaxine may accelerate neuronal maturation in the dentate gyri of adult male rats

Adult hippocampal neurogenesis has been linked to the effects of anti-depressant drugs on behavior in rodent models of depression. To explore this link further, we tested whether the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine impacted adult hippocampal neurogenesis differently than its primary active SNRI metabolite desvenlafaxine. Adult male Long Evans rats (n = 5-6 per group) were fed vehicle, venlafaxine (0.5 or 5 mg) or desvenlafaxine (0.5 or 5 mg) twice daily for 16 days. Beginning the third day of drug treatment, the rats were given a daily bromodeoxyuridine (BrdU; 50 mg/kg) injection for 5 days to label dividing cells and then perfused 2 weeks after the first BrdU injection to confirm total new hippocampal cell numbers and their phenotypes. The high desvenlafaxine dose increased total new BrdU+ cell number and appeared to accelerate neuronal maturation because fewer BrdU+ cells expressed maturing neuronal phenotypes and more expressed mature neuronal phenotypes in the dentate gyri of these versus vehicle-treated rats. While net neurogenesis was not increased in the dentate gyri of rats treated with the high desvenlafaxine dose, significantly more mature neurons were detected. Our data expand the body of literature showing that antidepressants impact adult neurogenesis by stimulating NPC proliferation and perhaps the survival of neuronal progeny and by showing that a high dose of the SNRI antidepressant desvenlafaxine, but neither a high nor low venlafaxine dose, may also accelerate neuronal maturation in the adult rat hippocampus. These data support the hypothesis that hippocampal neurogenesis may indeed serve as a biomarker of depression and the effects of antidepressant treatment, and may be informative for developing novel fast-acting antidepressant strategies.

Ziprasidone hydrocloride: what role in the management of schizophrenia?

Background

Since schizophrenia is considered one of the top ten causes of disease-related disability in the world, the development of second-generation (atypical) antipsychotics (SGAs) has increased the hopes of psychiatrists. SGAs, however, cannot be considered a unique pharmacological class since each SGA has many complex pharmacologic actions, only some of which are shared with other SGAs. Even though manyantipsychotics have similar efficacy on average, prescribers may be able to achieve better than average results by considering differences in selecting a specific drug for a specific patient. Clinicians know that each patient is unique. In order to achieve best outcomes for the individual patient, the better therapy is the therapy tailored for the single patient.

Objectives

With this article, we provide information on a relatively new antipsychotic ziprasidone released in 2001 by Pfizer for the treatment of schizophrenia. Compared with other first line atypical antipsychotics ziprasidone has a unique profile due to potent interaction with serotonergic receptors and lesser action upon α1 adrenergic, H1 and M1 antagonist activities. This paper describes the development of ziprasidone, its unique properties and its metabolically-friendly profile including its receptor binding affinities, pharmacokinetics, CNS activity results of clinical efficacy and relevant clinical trials. Safety, efficacy and patient preference are also examined. The available literature on ziprasidone of the last five years is reviewed.

CNS drug development: Part II: Advances from the 1960s to the 1990s

This column is the second in a series on central nervous system (CNS) drug development. The goal of this series is to explain to practicing clinicians how drugs are developed and why CNS drug development is at an important juncture involving both significant challenges and opportunities. This column (Part 2) reviews the history of CNS drug development from the 1960s to the 1990s. During the 1960s, researchers acquired a much clearer understanding of basic CNS pharmacology (e.g., biogenic amine transmitter systems in the brain) and developed the first animal models of psychiatric illness that could be used to test potential psychiatric medications. During the 1970s, drug development scientists used their expanded understanding of receptor binding affinity and the theories and techniques developed in the 1950s and 1960s to produce new CNS-active medications. They did this by adding or reducing affinities for certain regulatory proteins (e.g., receptors) to increase positive effects and/or minimize adverse effects. The development of newer antipsychotics and antidepressants is discussed to illustrate this process. The next column in this series will review CNS drug development during the first decade of the 21st century and discuss what directions we can expect the field to take in the next 10 to 20 years.