Pharmacological management of schizophrenia in older patients

Schizophrenia in the elderly: a special case requiring special management?

As the life expectancy of the general population increases, the population of elderly people with schizophrenia is also expected to increase. Consideration of the particular needs of these patients and the challenges associated with their management is therefore important [45].

Pharmacokinetics of quetiapine in elderly patients with selected psychotic disorders

OBJECTIVE

To assess the pharmacokinetics and tolerability of quetiapine in elderly patients with selected psychotic disorders.

STUDY DESIGN

This was a multicentre, open-label, 27-day, rising multiple-dose trial. Descriptive statistics summarised plasma quetiapine concentrations and pharmacokinetic parameters by trial day. A two-way analysis of variance was used to evaluate all pharmacokinetic parameters, and 90% confidence intervals of the mean differences were calculated.

METHODS

Antipsychotic drugs taken prior to the study period were discontinued on day 1. Quetiapine treatment began on day 3. Doses were increased stepwise, starting at 25mg three times daily and reaching 250mg three times daily by day 21.

PATIENTS

Twelve patients (age 63-85 years) with schizophrenia, schizoaffective disorder or bipolar disorder.

MAIN OUTCOME MEASURES AND RESULTS

Key assessments included quetiapine plasma concentrations, and neurological and safety evaluations. Under steady-state conditions, the 100 and 250mg doses of quetiapine were not significantly different in terms of dose-normalised area under the plasma concentration-time curve within an 8-hour dose administration interval, or in dose-normalised minimum plasma concentration (C(min)) at the end of a dose administration interval. The morning C(min) values for the seven discrete dose amounts evaluated also increased linearly with dose. The apparent oral clearance, volume of distribution and half-life did not change as a function of dose. There were no serious adverse events. The most common adverse events were postural hypotension (n = 6), dizziness (n = 5) and somnolence (n = 4).

CONCLUSIONS

While quetiapine was well tolerated at doses up to 250mg three times daily, the potential for reduced clearance, as well as the adverse effects of postural hypotension and dizziness, indicated that quetiapine should be introduced at lower doses and titrated at a relatively slower rate in patients > or =65 years.

Clinical effectiveness of atypical antipsychotics in elderly patients with psychosis

The elderly represent a unique patient group in the sense that they have a high prevalence of psychotic symptoms that are a manifestation of a variety of psychiatric, neurological and organic disorders. Treatment is complicated by several factors including comorbid diagnoses (psychiatric and medical), polypharmacy, age-related changes in pharmacokinetics and pharmacodynamics and high susceptibility to adverse events. Elderly patients require pharmacological interventions that are effective in reducing symptoms but also are well tolerated, improve everyday functioning, subjective well-being and treatment adherence and reduce family/career burden. The ability of an antipsychotic to fulfil these requirements determines its clinical effectiveness. To date, few studies have investigated the clinical effectiveness of atypical antipsychotics in elderly patients. However, clear differences exist between the available agents, particularly with regard to tolerability profiles, which have a major impact on the clinical outcome of patients. Clinicians should select an agent that is not only effective in reducing psychotic symptoms but, more importantly, one that has a low incidence of adverse events, such as extrapyramidal symptoms (EPS) and neurocognitive problems, which are of concern in the elderly.

Age-related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications

Advancing age is characterized by impairment in the function of the many regulatory processes that provide functional integration between cells and organs. Therefore, there may be a failure to maintain homeostasis under conditions of physiological stress. The reduced homeostatic ability affects different regulatory systems in different subjects, thus explaining at least partly the increased interindividual variability occurring as people get older. Important pharmacokinetic and pharmacodynamic changes occur with advancing age. Pharmacokinetic changes include a reduction in renal and hepatic clearance and an increase in volume of distribution of lipid soluble drugs (hence prolongation of elimination half-life) whereas pharmacodynamic changes involve altered (usually increased) sensitivity to several classes of drugs such as anticoagulants, cardiovascular and psychotropic drugs. This review focuses on the main age-related physiological changes affecting different organ systems and their implications for pharmacokinetics and pharmacodynamics of drugs.

The efficacy and safety of olanzapine for the treatment of geriatric psychosis

Elderly psychiatric patients often present with psychotic symptoms that need antipsychotic treatment. Olanzapine is one of the atypical antipsychotics with efficacy for psychotic symptoms and a safer side-effect profile than typical antipsychotics. This study was conducted to assess the efficacy and safety of olanzapine for treatment of geriatric psychosis. The sample population comprised 94 acute-ward patients who were 65 years of age or older. Clinical assessment was conducted at baseline and also at 4 weeks after commencement of olanzapine treatment, with use of the Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression Improvement (CGI-I) instruments. A 4-week therapeutic evaluation was completed for 80 patients, 73 of whom (91.3%) experienced mild to substantial improvement as determined from the CGI-I. A mean 52.6% reduction from baseline was also determined from the BPRS. The mean daily dosage of olanzapine in the fourth week was 10.1 +/- 5.3 mg/d (range, 2.5-20.0). Higher olanzapine dosages were administered for patients with functional psychoses than for an analogous group with organic mental disorders. Adverse effects were monitored for all 94 patients, the most common of which were somnolence (18.1%), dizziness (18.1%), and weakness of legs or bradykinesia (16.0%). Body weight and fasting triglyceride and sugar levels were significantly elevated after olanzapine treatment (2.2, 39.9, and 8.9% from baseline, respectively). It seems reasonable to suggest that olanzapine is efficacious for geriatric patients with psychosis and that the dosage should be diagnosis-dependent.

How much are atypical antipsychotic agents being used, and do they reach the populations who need them? A Canadian experience

BACKGROUND

The introduction of new antipsychotic agents in the past decade has helped alter the treatments available to 2 vulnerable populations-those with schizophrenia and related psychotic conditions and elderly individuals with dementia.

OBJECTIVE

After examining overall trends in antipsychotic use, this analysis reviews patterns of atypical antipsychotic use in the elderly and financially disadvantaged populations of Ontario. It identifies affected subpopulations and offers several interpretations of how observed patterns of use reflect outpatient prescribing practices.

METHODS

This study used drug claims data from the Ontario Drug Benefit (ODB) program for the years 1992 to 1998. The use of antipsychotic agents was followed for 2 years in a subpopulation of ODB participants identified as consistent users of these agents (ie, those with evidence of > 1-time use).

RESULTS

During the study period, the total number of ODB claimants grew by 1%, the number of claimants using antipsychotic agents increased by approximately 25%, and the expenditure per claimant in this group increased by nearly 250%. Much of this growth in expenditures was associated with use of the newer atypical antipsychotic agents olanzapine, risperidone, and quetiapine. Compared with patients aged > or = 65 years, those aged < 65 years were more likely to receive an initial prescription for an atypical antipsychotic or be switched to an atypical antipsychotic. However, the proportion of patients aged > 85 years consistently using antipsychotic agents was greater than predicted based on the proportion of the ODB population they represent. These patients were more likely to use conventional antipsychotic agents exclusively.

CONCLUSIONS

The introduction of the atypical antipsychotic agents was paralleled by a striking increase in ODB expenditures for antipsychotic drugs, although use of these agents was not consistent across age groups. There was more switching to atypical antipsychotics, as well as greater use in general, among younger compared with older patients, despite evidence that the atypical antipsychotics may be safer in the elderly than conventional antipsychotics. Guideline dissemination may be an important way of familiarizing clinicians with the atypical agents. Health care systems should be aware of the potential for a substantial increase in health care costs with more widespread adoption of these medications.

Antipsychotic medications and the elderly: effects on cognition and implications for use

Despite being frequently prescribed in the elderly, antipsychotic medications are commonly associated with adverse effects in this population, including sedative, orthostatic and extrapyramidal adverse effects. Growing evidence suggests that antipsychotics can also cause deleterious cognitive effects in some elderly patients. Preclinical and growing clinical evidence indicates that inhibitory effects on dopaminergic, cholinergic and histaminergic neurochemical systems may account for antipsychotic-associated cognitive impairment in the elderly. A review of published reports of the cognitive effects of antipsychotics in the elderly suggests that newer antipsychotic medications may possess a more favourable cognitive profile than that of traditional agents in this population. The cognitive effect that a specific antipsychotic will have in the elderly, however, is likely better predicted by considering the pharmacodynamic action of an individual agent in combination with the pathophysiology of the condition being treated. Agents with relatively weak dopamine inhibiting effects (e.g. clozapine and quetiapine), for example, would theoretically have a cognitive profile superior to that of agents with higher degrees of dopaminergic inhibition (all traditional agents, risperidone, olanzapine and ziprasidone) when used for conditions associated with diminished dopamine function (e.g. idiopathic Parkinson's disease). Drugs with weak anticholinergic effects (high-potency traditional agents, risperidone, quetiapine and ziprasidone) would theoretically be less likely to cause cognitive impairment than agents with high degrees of cholinergic receptor blocking actions (clozapine and olanzapine) when treating patients with impaired cholinergic function (e.g. Alzheimer's disease). Cholinergic agonist effects of clozapine and olanzapine may, however, mitigate potential adverse cognitive effects associated with the cholinergic blocking actions of these agents. Large, rigorous trials comparing the cognitive effects of antipsychotics with diverse pharmacodynamic actions are lacking in the elderly and are needed.

Long-Term use of quetiapine in elderly patients with psychotic disorders

BACKGROUND

Quetiapine is an atypical antipsychotic agent that does not appear to increase patient risk for treatment-emergent extrapyramidal symptoms (EPS) or anticholinergic symptoms. Previous studies of quetiapine use in elderly patients with schizophrenia and other psychoses examined short-term administration (< or = 12 weeks). Given the growing elderly population, the commensurate increase in elderly patients with psychoses, and the expected increase in disease treatment-years, the effect of long-term quetiapine administration in older patients is of considerable interest.

OBJECTIVE

This study assesses the long-term tolerability, safety, and clinical benefit of quetiapine in elderly patients with psychosis.

METHODS

Elderly patients (> or = 65 years of age) with psychotic disorders, as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, participated in this 52-week, open-label, multicenter trial. Investigators increased (and later adjusted) daily doses of quetiapine on the basis of clinical response and tolerability, and assessed safety and efficacy. Efficacy assessments were made using the 18-item Brief Psychiatric Rating Scale (BPRS), Clinical Global Impressions (CGI), Simpson-Angus Scale, and the Abnormal Involuntary Movement Scale (AIMS). For patients who withdrew before week 52, analyses were performed using observed data and the last observation carried forward.

RESULTS

One hundred eighty-four patients with psychotic disorders (98 women and 86 men) with a mean age of 76.1 years entered the trial. Seventy-two percent had psychotic disorders due to general medical conditions such as Alzheimer's disease, and 28% had other psychotic disorders, most commonly schizophrenia. Overall, 89 (48%) patients completed treatment through 52 weeks. Median total daily dose was 137.5 mg. Reasons, for withdrawal included lack of efficacy (19%), adverse events or intercurrent illness (15%), failure to return for follow-up (13%), protocol noncompliance (3%), and diminished need for treatment (2%). Somnolence (31%), dizziness (17%), and postural hypotension (15%) were common adverse events, but they rarely resulted in withdrawal from therapy. EPS-related adverse events occurred in 13% of patients. At end point (week 52), mean total score on the Simpson-Angus Scale had decreased from baseline by 1.8 points, whereas changes in AIMS scores were negligible. No clinically important effects were reported relative to mean changes in hematologic, thyroid function, or hepatic function variables. Quetiapine treatment appeared to have no associated cardiovascular adverse outcomes despite cardiovascular comorbidities and unrestricted use of concomitant cardiovascular medications. Significant decreases in BPRS total score (n = 170, P < 0.001) and CGI Severity of Illness item score (n = 177, P < 0.002) were seen at end point (observed data and last observation carried forward). Decreases of > or = 20% in mean BPRS total score were observed in 83 (49%) patients.

CONCLUSIONS

These results provide preliminary information to clinicians regarding tolerability, safety, and clinical improvement with quetiapine in elderly patients with psychotic symptoms, and support controlled studies of quetiapine in this patient population.