Antipsychotic maintenance treatment of schizophrenia patients: is there a consensus?

Pharmacokinetics and brain distribution studies of perphenazine-loaded solid lipid nanoparticles

BACKGROUND

Perphenazine (PPZ) is a typical antipsychotic that is mainly administrated for the treatment of schizophrenia. Due to its highly lipophilic nature and extensive hepatic first-pass metabolism, its oral bioavailability is low (40%).

OBJECTIVE

The novel nanocarriers like solid lipid nanoparticles (SLN) have been reported to be highly effective for improving the therapeutic effect of drugs. Therefore the main scope of the present investigation was the evaluation of in vivo characteristics of PPZ-SLN in terms of pharmacokinetic parameters and brain distribution.

METHODS

The PPZ-SLN was prepared by the solvent-emulsification and evaporation method. The storage stability of PPZ-SLN and empty SLN powders was studied for 3 months. In vivo pharmacokinetic studies and brain distribution evaluations were performed following a single oral dose administration of PPZ and PPZ-SLN suspensions on male Wistar rats. An HPLC method was established and validated for the quantitative determination of PPZ in plasma and brain samples.

RESULTS

The storage stability studies revealed the good storage stability of the both PPZ-SLN and empty SLN at 4 °C. Compared to PPZ suspension, the relative bioavailability and the brain distribution of PPZ-SLN were increased up to 2-fold and 16-fold, respectively. Mean residence time (MRT) and half-life (t_1/2) of PPZ-SLN were significantly (p value < 0.01) increased in both plasma and brain homogenate compared to PPZ suspension.

CONCLUSION

The significant improvement in the pharmacokinetic properties of PPZ following one oral dose indicates that SLN is a promising drug delivery system for PPZ and shows a high potential for successful brain delivery of this antipsychotic.

Trends in the pharmacological treatment of patients with schizophrenia over a 12 year observation period

In this study we evaluated whether our efforts to promote evidence-based guidelines for the psychopharmacological treatment of patients with schizophrenia have led to measurable changes of treatment practice in our hospital by investigating three primary hypotheses: 1) Polypharmacy has become less common in recent years, 2) Conventional neuroleptics have been replaced by second generation antipsychotics; and 3) Dosing regimes have changed towards lower doses. We have therefore collected data from the clinical records of all in-patients with ICD-9/ICD-10 diagnoses of schizophrenia hospitalized at the Department of Psychiatry of the Medical University Innsbruck in the years 1989, 1995, 1998 and 2001. Data from 1989 to 1998 showed a significant decrease in the use of two or more antipsychotics given simultaneously. Contrary to our hypothesis, there was a significant increase in polypharmacy between 1998 and 2001. The predominant use of second generation antipsychotics became standard in schizophrenia treatment. In this context the decrease of concomitant anticholinergic medication is notable. Doses of conventional antipsychotics like haloperidol as well as doses of risperidone decreased whereas doses of other second generation antipsychotics increased. All in all, the pharmacological management of schizophrenia patients is increasingly in tune with current treatment guidelines.

Compliance with antipsychotic treatment

OBJECTIVE

Despite the demonstrated efficacy of antipsychotics the relapse rate among patients with schizophrenia remains high. One major reason for this is non-compliance. In this article we review different factors influencing compliance and discuss possibilities to enhance compliance among schizophrenic patients.

METHOD

This review is based on a systematic literature search in Medline.

RESULTS

We summarize the four main factors (patient-, environment-, physician- and treatment-related) that influence compliance and discuss possible measures to enhance compliance. Next to many other variables discussed in more detail, it is crucial to ensure a positive doctor-patient relationship and to provide sufficient information about the benefit/risk ratio of the medication as well as about the illness itself to build up and sustain compliance. Significant others should be included into the therapeutic alliance whenever possible.

CONCLUSION

Despite many published reports on compliance, it remains to be a problem of eminent clinical relevance. Clinicians must not underestimate it in order to optimize the treatment of patients with schizophrenia.

A comparison of patients' and prescribers' beliefs about neuroleptic side-effects: prevalence, distress and causation

Neuroleptic side-effects adversely affect clinical outcome in schizophrenic patients. Clinicians therefore require an understanding of the impact of such side-effects. This study compared psychiatrists' estimates of the prevalence of neuroleptic side-effects and associated distress with schizophrenic patients' reports of side-effects and distress. Psychiatrists were asked to estimate the likelihood of informing patients about side-effects. Psychiatrists' estimates of prevalence but not of distress correlated significantly with patients' reports. Psychiatrists' avowed decisions to inform patients about side-effects were significantly correlated with their estimates of prevalence and distress, but not with patients' reported levels of distress. Patients were unlikely to attribute side-effects to neuroleptic medication. These results indicate that patients and psychiatrists share similar views about the prevalence and implications of neuroleptic side-effects. However, psychiatrists' apparent lack of understanding of which side-effects are most likely to cause distress to patients may adversely affect the therapeutic alliance between prescribers and consumers.

Closing the gap between research and practice

Has Mrs A got schizophrenia? Would Mr B do better with a tricyclic or a selective serotonin reuptake inhibitor? Is Miss C likely to be recovered in six months time? Is St John's wort an effective antidepressant? Clinical psychiatry involves making difficult decisions about diagnosis, therapy and prognosis. Sometimes we may be entirely confident about our decisions, but often we are uncomfortably aware that we are making a choice without being sure there is convincing evidence to justify it. Maybe we don't know or have forgotten what the evidence is, or perhaps there isn't any.

The social construction of drug debates

Drug debates normally proceed without scrutiny of why the particular issues being debated are considered the crucial issues. One plausible influence on the terms of debates is the interest groups involved. Four drug debates are addressed in this paper: neuroleptics, drugs in sport, analgesics and marijuana. The key interest groups and their likely influence on the terms of debates are examined. The implication of this analysis is that more attention should be directed to the terms of drug debates rather than just arguing within those terms.