A single-dose study of the pharmacodynamic effects of chlormethiazole, temazepam and placebo in elderly parkinsonian patients

WITHDRAWN: Benzodiazepines and related drugs for insomnia in palliative care

This review is out of date, and the original authors are no longer available to update it.

The editorial group responsible for this previously published document have withdrawn it from publication.

Lewy body and parkinsonian dementia: common, but often misdiagnosed conditions

BACKGROUND

Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) are the two most common types of dementing neurodegenerative disease after Alzheimer's disease (AD). Both of these conditions are often diagnosed late or not at all.

METHODS

Selective literature review.

RESULTS

The severe cholinergic and dopaminergic deficits that are present in both DLB and PDD produce not only motor manifestations, but also cognitive deficits, mainly in the executive and visual-constructive areas, as well as psychotic manifestations such as visual hallucinations, delusions, and agitation. The intensity of these manifestations can fluctuate markedly over the course of the day, particularly in DLB. Useful tests for differential diagnosis include magnetic resonance imaging and electroencephalography; in case of clinical uncertainty, nuclear medical procedures and cerebrospinal fluid analysis can be helpful as well. Neuropathological studies have revealed progressive alpha-synuclein aggregation in affected areas of the brain. In DLB, beta-amyloid abnormalities are often seen as well.

CONCLUSION

DLB should be included in the differential diagnosis of early dementia. If motor manifestations arise within one year (DLB), dopaminergic treatment should be initiated. On the other hand, patients with Parkinson's disease should undergo early screening for signs of dementia so that further diagnostic and therapeutic steps can be taken in timely fashion, as indicated. Cholinesterase inhibitors are useful for the treatment of cognitive deficits and experiential/behavioral disturbances in both DLB (off-label indication) and PDD (approved indication).

Benzodiazepines and related drugs for insomnia in palliative care

BACKGROUND

Insomnia, a subjective complaint of poor sleep and associated impairment in daytime function, is a common problem. Currently, benzodiazepines are the most used pharmacological treatment for this complaint. They are considered helpful for occasional short-term use up to four weeks but longer term use is not advised due to potential problems regarding tolerance, dosing escalation, psychological addiction and physical dependence. There is no consensus on their utility in patients with progressive incurable conditions who may require assistance with sleep for many weeks as their condition deteriorates.

OBJECTIVES

To assess the effectiveness and safety of benzodiazepines or benzodiazepine receptor agonists such as Zolpidem, Zopiclone and Zaleplon for insomnia in palliative care.

SEARCH STRATEGY

Several electronic databases were searched including Cochrane PaPaS Group specialized register, Cochrane Library Issue 4, 2001, MEDLINE, EMBASE, BNI plus, CINAHL, BIOLOGICAL ABSTRACTS, PSYCINFO, CANCERLIT, HEALTHSTAR, WEB OF SCIENCE, SIGLE, Dissertation Abstracts, ZETOC and the MetaRegister of ongoing trials. These were searched from 1960 to 2001 or as much of this range as possible. Additional articles were sought by handsearching reference lists in standard textbooks and reviews in the field and by contacting academic centres in palliative care and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Studies considered for inclusion were randomized controlled trials of adult patients in any setting, receiving palliative care or suffering an incurable progressive medical condition. (For example, cancers, AIDS, Motor Neurone Disease, Multiple Sclerosis, Parkinson's Disease, Chronic Obstructive Pulmonary Disease). There had to be an explicit complaint of insomnia in study participants, diagnosed by any of the three main classification systems (DSM-IV (APA 1994), ICSD (AASD 1990) or ICD (WHO 1992)), or as described in the study if it involved a subjective complaint of poor sleep. Studies had to compare a benzodiazepine or Zolpidem or Zopiclone or Zaleplon with placebo or active control for the treatment of insomnia. Any duration of therapy were considered.

DATA COLLECTION AND ANALYSIS

Abstracts were independently inspected by both reviewers, full papers were obtained where necessary. Where there was uncertainty advice was sought by a third (PW). Data extraction and quality assessments were undertaken independently by both reviewers.

MAIN RESULTS

No randomized controlled trials were identified meeting the a priori inclusion criteria. Thirty-seven studies were considered but all were excluded from the review.

REVIEWER'S CONCLUSIONS

Despite a comprehensive search no evidence from randomized controlled trials was identified. It was not possible to draw any conclusions regarding the use of benzodiazepines in palliative care.

Influence of benzodiazepines on antiparkinsonian drug treatment in levodopa users

OBJECTIVES

Animal studies showed that benzodiazepines decrease the concentration of dopamine in the striatum. Benzodiazepines may therefore affect the treatment of Parkinson's disease. This study determined whether start of a benzodiazepine in patients on levodopa was followed by a faster increase of antiparkinsonian drug treatment.

METHODS

Data came from the PHARMO database, which includes information on drug dispensing for all residents of six Dutch cities. Selected were all patients aged 55 years and older who used levodopa for at least 360 days. The rate of increase of antiparkinsonian drug treatment was compared between starters of a benzodiazepine and controls who did not start a benzodiazepine with the use of Cox's proportional hazard model.

RESULTS

Identified were 45 benzodiazepine starters (27 women, mean age 76.4 years) and 169 controls (83 women, 74.3 years). Antiparkinsonian drug treatment increased faster in the benzodiazepine group; relative risk was 1.44 (95% confidence interval 0.80-2.59).

CONCLUSION

This study has not found any statistically significant increase in antiparkinsonian drug treatment when a benzodiazepine was started in a small population of chronic levodopa users.

Vigilance in schizophrenia and its disruption by impaired pre-attentive selection: a dysintegration hypothesis

INTRODUCTION

The study determined, simultaneously, whether major deficits of schizophrenia (sustained and selective attention, slow information processing, slow motor responding) are independent or related to each other.

METHODS

An auditory vigilance task (Pigache Attention Task, PAT) required a button-press to targets during four 5-minute subtests (slow diotic, fast diotic, slow dichotic, fast dichotic, analogous to four versions of the continuous performance test). Twenty schizophrenics on the first test-occasion of a double-blind, placebo controlled, crossover study were compared to 11 healthy subjects. Also, all 28 fortnightly test occasions were analysed to quantify the schizophrenia deficits more precisely and the PAT was evaluated in a larger group of 86 healthy subjects.

RESULTS

Schizophrenics were significantly impaired on all task parameters versus healthy subjects. The patients' errors were independent and additive (grand mean components: basic task 36%, including a 9% time-on-task component; speed increment 26%; dichotic increment 38%). Errors, latencies, and psychosis severity were mutually correlated.

CONCLUSIONS

The performance of all subjects confirmed a quantitative Vigilance Decision Model. The PAT impairments in schizophrenia suggested that rival options (e.g. thoughts) redeployed or suppressed attention away from the task , indicating a dysfunction of pre-attentive selection processes. Brain mechanisms are discussed and a new dys integration hypothesis of schizophrenia is proposed.

Pharmacokinetics and pharmacodynamics of clomethiazole after oral and rectal administration in healthy subjects

Clomethiazole, a sedative-hypnotic and anticonvulsant drug, has been successfully administered orally and intravenously, but in cases where either of these methods presents complications, rectal administration may represent a practical alternative. We sought to compare the single-dose pharmacokinetics and pharmacodynamics of clomethiazole after oral and rectal administration. Ten healthy adult volunteers were given 600 mg clomethiazole edisylate (corresponding to 390 mg clomethiazole base) in 2 capsules as a single oral or rectal dose in a double-masked, double-dummy, crossover fashion. Serum concentrations were measured up to 10 hours after administration using a specific high-performance liquid chromatography method. Computerized reaction-time measurement and visual analogue scales (VAS) were used to assess drug effects. Peak serum concentrations were significantly higher after oral administration (mean +/- SEM, oral 1.76 +/- 0.47 microg/mL vs rectal 0.48 +/- 0.14 microg/mL; P = 0.03) and appeared earlier (55 +/- 12 vs 89 +/- 11 min; P = 0.04). Area under the concentration-time curve values were similar after administration by both routes (oral 116 +/- 20.6 vs rectal 105 +/- 36.0 microg x min/mL), with a relative rectal bioavailability of 90% compared with oral administration. The objective pharmacodynamic effects on reaction time (increase of 104 +/- 26 vs 66 +/- 22 ms, oral vs rectal) and working speed (decrease of 132 +/- 38 vs 97 +/- 32 ms, oral vs rectal) were not significantly different. Subjective pharmacodynamic effects, as measured on the VAS, were comparable with both routes of administration. Clomethiazole was well tolerated, with a similar adverse effect profile for both routes of administration. The effects of rectal dosing of clomethiazole were similar to those of oral dosing but appeared to occur later. Our results suggest that rectal administration of a single 600-mg clomethiazole edisylate dose bears no safety risk. Therefore, rectal administration could be considered when neither oral nor parenteral administration is possible and a later onset of effect is not critical.