Acute and subchronic effects of nefazodone and imipramine on highway driving, cognitive functions, and daytime sleepiness in healthy adult and elderly subjects

[Reduced mobility in the elderly due to medication, alcohol, and cannabinoids]

Many diseases are accompanied by symptoms that can impair the ability to perform complex everyday tasks, such as active participation in road traffic. If a cure is not possible, the aim of drug therapy is to alleviate the symptoms to such an extent that the patient no longer has any restrictions in everyday life. However, around 20% of the approximately 100,000 medicines licensed in Germany have traffic-relevant side effects that can also lead to driving impairment.It is assumed that the effect of a drug is at least partially responsible for one in four traffic accidents and that one in ten victims of fatal road accidents has taken psychotropic drugs before driving. In addition to alcohol and drugs, medications from the benzodiazepine, opioid, and antidepressant groups are suspected of impairing driving safety in particular. The effects of these substances on young people have been described many times, but this review deals specifically with the traffic-relevant (side) effects of various classes of drugs on elderly people (aged 65 and over).Older people in particular often have to take different medications, which are metabolized differently compared to younger people due to underlying diseases and can also interact with each other. It was found that (1) older people often react more sensitively to substances, (2) not all representatives of a drug class have the same effect on driving safety, and (3) a general assessment of a drug's safety is not possible, since the effects also depend on other factors such as underlying diseases, treatment regimen, and the time of day the medication is taken.

Inhibitory Actions of Antidepressants, Hypnotics, and Anxiolytics on Recombinant Human Acetylcholinesterase Activity

Alzheimer's disease (AD) is accompanied by behavioral and psychological symptoms of dementia (BPSD), which is often alleviated by treatment with psychotropic drugs, such as antidepressants, hypnotics, and anxiolytics. If these drugs also inhibit acetylcholinesterase (AChE) activity, they may contribute to the suppression of AD progression by increasing brain acetylcholine concentrations. We tested the potential inhibitory effects of 31 antidepressants, 21 hypnotics, and 12 anxiolytics on recombinant human AChE (rhAChE) activity. At a concentration of 10-4 M, 22 antidepressants, 19 hypnotics, and 11 anxiolytics inhibited rhAChE activity by <20%, whereas nine antidepressants (clomipramine, amoxapine, setiptiline, nefazodone, paroxetine, sertraline, citalopram, escitalopram, and mirtazapine), two hypnotics (triazolam and brotizolam), and one anxiolytic (buspirone) inhibited rhAChE activity by ≥20%. Brotizolam (≥10-6 M) exhibited stronger inhibition of rhAChE activity than the other drugs, with its pIC50 value being 4.57 ± 0.02. The pIC50 values of the other drugs were <4, and they showed inhibitory activities toward rhAChE at the following concentrations: ≥3 × 10-6 M (sertraline and buspirone), ≥10-5 M (amoxapine, nefazodone, paroxetine, citalopram, escitalopram, mirtazapine, and triazolam), and ≥3 × 10-5 M (clomipramine and setiptiline). Among these drugs, only nefazodone inhibited rhAChE activity within the blood concentration range achievable at clinical doses. Therefore, nefazodone may not only improve the depressive symptoms of BPSD through its antidepressant actions but also slow the progression of cognitive symptoms of AD through its AChE inhibitory actions.

Cholinergic and serotonergic modulation of resting state functional brain connectivity in Alzheimer's disease

Disruption of cholinergic and serotonergic neurotransmitter systems is associated with cognitive, emotional and behavioural symptoms of Alzheimer's disease (AD). To investigate the responsiveness of these systems in AD we measured the effects of a single-dose of the selective serotonin reuptake inhibitor citalopram and acetylcholinesterase inhibitor galantamine in 12 patients with AD and 12 age-matched controls on functional brain connectivity with resting state functional magnetic resonance imaging. In this randomized, double blind, placebo-controlled crossover study, functional magnetic resonance images were repeatedly obtained before and after dosing, resulting in a dataset of 432 scans. Connectivity maps of ten functional networks were extracted using a dual regression method and drug vs. placebo effects were compared between groups with a multivariate analysis with signals coming from cerebrospinal fluid and white matter as covariates at the subject level, and baseline and heart rate measurements as confound regressors in the higher-level analysis (at p < 0.05, corrected). A galantamine induced difference between groups was observed for the cerebellar network. Connectivity within the cerebellar network and between this network and the thalamus decreased after galantamine vs. placebo in AD patients, but not in controls. For citalopram, voxelwise network connectivity did not show significant group × treatment interaction effects. However, we found default mode network connectivity with the precuneus and posterior cingulate cortex to be increased in AD patients, which could not be detected within the control group. Further, in contrast to the AD patients, control subjects showed a consistent reduction in mean connectivity with all networks after administration of citalopram. Since AD has previously been characterized by reduced connectivity between the default mode network and the precuneus and posterior cingulate cortex, the effects of citalopram on the default mode network suggest a restoring potential of selective serotonin reuptake inhibitors in AD. The results of this study also confirm a change in cerebellar connections in AD, which is possibly related to cholinergic decline.

Evaluation method regarding the effect of psychotropic drugs on driving performance: A literature review

Although automobile driving is necessary for many people, including patients with mental disorders, the influence of psychotropic drugs on driving performance remains unclear and requires scientific verification. Therefore, the objective of this study was to conduct a review of the literature in order to aid the development of a valid evaluation method regarding the influence of medication on driving performance. We conducted a literature search using two sets of terms on PubMed. One set was related to psychotropic drugs, and the other to driving tests. We excluded reviews and case studies and added literature found on other sites. A total of 121 relevant reports were found. The experiments were roughly divided into on-the-road tests (ORT) and driving simulators (DS). Although highway driving tests in ORT are most often used to evaluate driving performance, DS are becoming increasingly common because of their safety and low cost. The validity of evaluation methods for alcohol should be verified; however, we found that there were few validated tests, especially for DS. The scenarios and measurement indices of each DS were different, which makes it difficult to compare the results of DS studies directly. No evaluation indices, except for SD of lateral position, were sufficiently validated. Although highway ORT are the gold standard, DS were shown to have an increasing role in evaluating driving performance. The reliability of DS needs to be established, as does their validation with alcohol in order to accumulate more high-quality evidence.

Prevention of relapse and recurrence of depression: newer versus older antidepressants

In a 17- to 19-year follow-up study it was shown that patients admitted to the Maudsley Hospital, London (whose index episode marked their first psychiatric contact) had a 50% chance of readmission during their lifetime; those with previous admissions had a similar chance of readmission within three years. Less than one-fifth of the patients had remained well, and over one-third suffered severe chronic distress and handicap or had died unnaturally (Lee & Murray, 1988). Similar gloomy pictures were reported in a 15-year follow-up study of patients in London and Sydney (Kilohet al, 1988) and an 11-year follow-up study of patients in Montreal (Lehmannet al, 1988). As a result of such findings, much emphasis is now put on the importance of continuation and maintenance treatment of depression.

Serotonergic and cholinergic modulation of functional brain connectivity: A comparison between young and older adults

Aging is accompanied by changes in neurotransmission. To advance our understanding of how aging modifies specific neural circuitries, we examined serotonergic and cholinergic stimulation with resting state functional magnetic resonance imaging (RS-fMRI) in young and older adults. The instant response to the selective serotonin reuptake inhibitor citalopram (30 mg) and the acetylcholinesterase inhibitor galantamine (8 mg) was measured in 12 young and 17 older volunteers during a randomized, double blind, placebo-controlled, crossover study. A powerful dataset consisting of 522 RS-fMRI scans was obtained by acquiring multiple scans per subject before and after drug administration. Group × treatment interaction effects on voxelwise connectivity with ten functional networks were investigated (p < .05, FWE-corrected) using a non-parametric multivariate analysis technique with cerebrospinal fluid, white matter, heart rate and baseline measurements as covariates. Both groups showed a decrease in sensorimotor network connectivity after citalopram administration. The comparable findings after citalopram intake are possibly due to relatively similar serotonergic systems in the young and older subjects. Galantamine altered connectivity between the occipital visual network and regions that are implicated in learning and memory in the young subjects. The lack of a cholinergic response in the elderly might relate to the well-known association between cognitive and cholinergic deterioration at older age.

Antidepressants and Driving in Older Adults: A Systematic Review

With an increasing number of older drivers who are prescribed antidepressants, the potential consequences of antidepressant use on driving skills in an aging population are becoming a pressing issue. We conducted a systematic review using MEDLINE, targeting articles specifically pertaining to antidepressants and driving in a population or subgroup of older adults (≥ 55 years of age). The search yielded 267 references, nine of which pertained to the effects of antidepressants on driving in older adults. The single experimental study found imipramine to have detrimental effects on highway driving, whereas nefazodone did not. Seven of eight population-based studies reported a significant increased risk of involvement in a collision associated with antidepressant use. Although the studies indicated a negative effect of antidepressants on driving, the epidemiological designs cannot exclude the possibility that the underlying illness, generally major depression, is the culprit.

Potentially Driver-Impairing Medications: Risks and Strategies for Injury Prevention

Impaired driving is a major cause of motor vehicle accidents, injury, and fatality. Several classes of medication have been found to affect a driver's cognition, judgment, and reaction time and may put patients at increased risk for accidents and injury. This article will explore medications with side effects posing a potential threat to drivers, including anxiolytics, sedative hypnotics, antihistamines, and antidepressants, as well as describe potential strategies for mitigating or minimizing such risks.

Concurrent Use of Benzodiazepines and Antidepressants and the Risk of Motor Vehicle Accident in Older Drivers: A Nested Case-Control Study

INTRODUCTION

Aging of the population results in an increase in senior drivers. Elderly are frequently treated with benzodiazepines and antidepressants. The objective of this study was to determine whether the concurrent use of benzodiazepines and antidepressants is associated with motor vehicle accidents (MVAs) in the elderly.

METHODS

This was a nested case-control study within a cohort of drivers aged 67-84 years between 1990 and 2000, identified from the Société de l'Assurance Automobile du Québec and the Régie de l'Assurance Maladie du Québec databases. First cases of MVAs during follow-up were matched with up to ten controls from the cohort. Odds ratios (ORs) for the association between MVA and the use of benzodiazepines and antidepressants were estimated using conditional logistic regression.

RESULTS

The cohort included 373,818 drivers, with 74,503 MVA cases matched with 744,663 controls. The risk of MVA was higher in current users of long-acting benzodiazepines [OR 1.23; 95% confidence interval (CI) 1.16-1.29] than in current users of short-acting benzodiazepines (OR 1.05; 95% CI 1.02-1.08). The risk of MVA was increased in current users of selective serotonin reuptake inhibitors (SSRIs; OR 1.13; 95% CI 1.04-1.22), while it was not in current users of tricyclic antidepressants (TCAs; OR 1.04; 95% CI 0.96-1.14). The highest ORs of MVA were observed in long-acting benzodiazepines users concurrently using SSRIs (OR 1.37; 95% CI 1.07-1.77, P value for interaction = 0.964) or TCAs (OR 1.54; 95% CI 1.21-1.95, P value for interaction = 0.077).

CONCLUSION

Use of long-acting benzodiazepines is associated with an increased risk of MVA in the elderly, particularly in those concurrently using SSRIs or TCAs.

Effects of central nervous system drugs on driving: speed variability versus standard deviation of lateral position as outcome measure of the on-the-road driving test

BACKGROUND

The on-the-road driving test in normal traffic is used to examine the impact of drugs on driving performance. This paper compares the sensitivity of standard deviation of lateral position (SDLP) and SD speed in detecting driving impairment.

METHODS

A literature search was conducted to identify studies applying the on-the-road driving test, examining the effects of anxiolytics, antidepressants, antihistamines, and hypnotics. The proportion of comparisons (treatment versus placebo) where a significant impairment was detected with SDLP and SD speed was compared.

RESULTS

About 40% of 53 relevant papers did not report data on SD speed and/or SDLP. After placebo administration, the correlation between SDLP and SD speed was significant but did not explain much variance (r = 0.253, p = 0.0001). A significant correlation was found between ΔSDLP and ΔSD speed (treatment-placebo), explaining 48% of variance. When using SDLP as outcome measure, 67 significant treatment-placebo comparisons were found. Only 17 (25.4%) were significant when SD speed was used as outcome measure. Alternatively, for five treatment-placebo comparisons, a significant difference was found for SD speed but not for SDLP.

CONCLUSIONS

Standard deviation of lateral position is a more sensitive outcome measure to detect driving impairment than speed variability.

A systematic review of amnestic and non-amnestic mild cognitive impairment induced by anticholinergic, antihistamine, GABAergic and opioid drugs

BACKGROUND

Mild cognitive deficits are experienced by 18% of community-dwelling older adults, many of whom do not progress to dementia. The effect of commonly used medication on subtle impairments in cognitive function may be under-recognized.

OBJECTIVE

The aim of the review was to examine the evidence attributing amnestic or non-amnestic cognitive impairment to the use of medication with anticholinergic, antihistamine, GABAergic or opioid effects.

METHODS

MEDLINE and EMBASE were searched for randomized, double-blind, placebo-controlled trials of adults without underlying central nervous system disorders who underwent detailed neuropsychological testing prior to and after oral administration of drugs affecting cholinergic, histaminergic, GABAergic or opioid receptor pathways. Seventy-eight studies were identified, reporting 162 trials testing medication from the four targeted drug classes. Two investigators independently appraised study quality and extracted relevant data on the occurrence of amnestic, non-amnestic or combined cognitive deficits induced by each drug class. Only trials using validated neuropsychological tests were included. Quality of the evidence for each drug class was assessed based on consistency of results across trials and the presence of a dose-response gradient.

RESULTS

In studies of short-, intermediate- and long-acting benzodiazepine drugs (n = 68 trials), these drugs consistently induced both amnestic and non-amnestic cognitive impairments, with evidence of a dose-response relationship. H(1)-antihistamine agents (n = 12) and tricyclic antidepressants (n = 15) induced non-amnestic deficits in attention and information processing. Non-benzodiazepine derivatives (n = 29) also produced combined deficits, but less consistently than benzodiazepine drugs. The evidence was inconclusive for the type of cognitive impairment induced by different bladder relaxant antimuscarinics (n = 9) as well as for narcotic agents (n = 5) and antipsychotics (n = 5). Among healthy volunteers >60 years of age, low doses of commonly used medications such as lorazepam 0.5 mg, oxybutynin immediate release 5 mg and oxycodone 10 mg produced combined deficits.

CONCLUSION

Non-amnestic mild cognitive deficits are consistently induced by first-generation antihistamines and tricyclic antidepressants, while benzodiazepines provoke combined amnestic and non-amnestic impairments. Risk-benefit considerations should be discussed with patients in order to enable an informed choice about drug discontinuation or substitution to potentially reverse cognitive adverse effects.

The prevalence and nature of stopped on-the-road driving tests and the relationship with objective performance impairment

INTRODUCTION AND OBJECTIVES

The on-the-road driving test in normal traffic is applied to examine the impact of drugs on driving performance. Although participants are accompanied by a licensed driving instructor, under Dutch law, the driver is primarily responsible for safe driving and is not permitted to continue driving when it is judged that the drug compromises safety. This review examined the prevalence and nature of stopped driving tests, and the relationship with Standard Deviation of Lateral Position (SDLP), i.e. the "weaving of the car".

MATERIALS AND METHODS

A literature search was conducted to gather all publications on clinical trials that applied the on-the-road driving test, examining the effects of Central Nervous System (CNS)-drugs such as anxiolytics, antidepressants, antihistamines, analgesics, and hypnotics.

RESULTS

47 papers reported on 50 Dutch clinical trials in which 1059 subjects participated (903 healthy volunteers and 156 patients). A total of 7232 driving tests were performed; 5050 after drug treatment and 2042 after placebo. 3.1% of all driving tests were terminated before completion: 4.1% after drug treatment, and 0.7% after placebo. The decision to stop a driving test was 3-4 times more often made by the driving instructor than the subject. The most common reasons for stopping were the driver feeling tired or sleepy, or the driving instructor noticing signs of drowsiness and performance impairment. Although SDLP values of stopped driving tests are sometimes high, there is no clear relationship between SDLP (changes from placebo) and the decision to stop a driving test. Based on 8 studies that reported exact data, 39.6% of stopped drivers had a lower and 60.4% had a higher SDLP than 35 cm, i.e. the cut-off point of safe driving. This confirms that perception of the driver as well as judgment by the instructor of driving to be 'unsafe' differs between individuals.

CONCLUSION

Driving tests are sometimes stopped after drug treatment or placebo. The decision to stop driving is not a good correlate of objective performance.

Antidepressants in healthy subjects: what are the psychotropic/psychological effects?

A wide debate is ongoing regarding whether antidepressant effects should be considered a general property of these agents or whether they exclusively belong to the context of target symptoms. The aim of the present review is to summarize findings on antidepressant influences on healthy volunteers, focusing on changes in psychological and cognitive functions. Differences have been detected between acute and chronic treatments. Acute treatment has been found to lead to positive bias in emotion processing and facilitation in negative emotion recognition. Chronic treatments have been found to stabilise some changes induced by acute treatment, such as increased social behaviours. Regarding antidepressant modulation of affective symptomatology contrasting results have been reported suggesting that the link between action on cognitive processes and mood may be not direct. In fact, meta-analyzing data on mood and anxiety symptoms no difference was detected between subjects receiving placebo and SSRIs. However, meta-analyzing data on negative affects, a significant decrease was detected in subjects receiving SSRIs in comparison with subjects receiving placebo. In summary, antidepressants seem to exert a detectable influence also in healthy subjects.

Insomnia pharmacology

Insomnia is not only the most common sleep disorder in the population, it is a frequent complaint heard overall by primary care physicians and specialists alike. Given the high prevalence of this disorder, its tendency to persist, and the frequency with which patients complain of symptoms in practice, it is imperative to have an understanding of basic sleep-wake mechanisms and the evolving field of pharmacologic approaches to enhance sleep. Currently, pharmacologic approaches are among the most widely used therapies for insomnia. This article reviews sleep-wake mechanisms, the neuroanatomic targets for sleep and wake-promoting agents, and discusses currently used agents to promote sleep and investigational hypnotics.

Highway driving in the elderly the morning after bedtime use of hypnotics: a comparison between temazepam 20 mg, zopiclone 7.5 mg, and placebo

A major problem related to hypnotic drug use is residual sedation the morning after bedtime administration. This constitutes a particular safety hazard for patients who have to drive a car the next morning. Information on the severity of residual effects is mainly derived from studies conducted with young healthy volunteers. However, most users of hypnotics are older people who may be more sensitive to drug effects. The aim of this study was to evaluate the residual effects the morning after evening doses of temazepam 20 mg and zopiclone 7.5 mg on driving performance in healthy elderly drivers. Eighteen healthy elderly drivers (10 females and 8 males; mean age, 64.3 years) participated in a double-blind, 3-way crossover study. Treatments were single oral doses of temazepam 20 mg, zopiclone 7.5 mg, and placebo administered at bedtime. Subjects performed a standardized highway driving test between 10 and 11 hours after hypnotic intake. Before and after the driving test, cognitive performance was assessed. Driving performance did not differ between temazepam and placebo but was significantly impaired after zopiclone 7.5 mg (P < 0.002). The results of the laboratory tests were in line with the effects on driving of both hypnotics. Temazepam 20 mg is unlikely to impair driving 10 hours or more after bedtime administration in healthy elderly aged 75 years or younger. Zopiclone 7.5 mg moderately impairs driving in the elderly at least until 11 hours after administration. The magnitude of impairing effects in the elderly was comparable with those found previously in younger volunteers.

Cognitive toxicity of pharmacotherapeutic agents used in social anxiety disorder

OBJECTIVE

To compare cognitive impairment of medications used in social anxiety disorder (SAD).

METHODS

Data from peer-reviewed publications (1975-2007) of controlled, crossover design, pharmacodynamic studies on SAD medications in healthy volunteers were analysed. The number of objective psychometrics for each drug/dose level at all time points after dosing, and of instances of statistically significant impairment of cognitive function, enabled calculation of drug-induced cognitive impairment. The magnitude of impairment between drugs was compared using proportional impairment ratios (PIRs).

RESULTS

Olanzapine, oxazepam, lorazepam and mianserin had twice the average cognitive toxicity of other treatments. Selective serotonin reuptake inhibitors (SSRIs) impaired cognition to a lesser extent than other pharmacological groupings. There was extensive intra-class variation: fluvoxamine (PIR = 0.08) possessed little detrimental cognitive activity, whereas sertraline (PIR = 5.33) caused impairment over five times the SSRI group average. Benzodiazepines caused noticeable cognitive impairment.

CONCLUSIONS

Substantial differences exist, both between and within therapeutic classes, in the behavioural toxicity of medications used for SAD.

Plasma amitriptyline level after acute administration, and driving performance in healthy volunteers

AIMS

Amitriptyline triggers the impairment of cognitive and motor functions and has been confirmed to have harmful effects on driving performance. Although interindividual differences in plasma concentration may cause variations in driving performance, the relationship between plasma amitriptyline concentration and its effect on driving performance has not been completely elucidated. Thus, the aim of the present study was to assess the influence of individual pharmacokinetic differences on driving performance and cognitive functions.

METHODS

In this double-blinded study, 17 healthy male volunteers were given an acute, single, 25-mg dose of amitriptyline. The subjects were assigned three driving simulator tasks, three cognitive tasks, and the questionnaire of the Stanford Sleepiness Scale at the baseline and at 4 h after dosing. The plasma amitriptyline concentrations were measured on high-performance liquid chromatography.

RESULTS

A significant positive correlation was observed between the plasma amitriptyline concentration and road-tracking performance (r = 0.543, P < 0.05). There was no significant correlation between the plasma amitriptyline concentration and other driving performance, cognitive functions, and subjective somnolence.

CONCLUSIONS

Amitriptyline produces a concentration-related impairment on road-tracking performance. Therapeutic monitoring of amitriptyline would be useful for predicting the difficulties involved while driving.

The effects of acute treatment with paroxetine, amitriptyline, and placebo on driving performance and cognitive function in healthy Japanese subjects: a double-blind crossover trial

OBJECTIVE

To assess the effects of antidepressants on driving performance from a different methodological viewpoint in light of the recent traffic accidents.

METHODS

In this double-blinded, 3-way crossover trial, 17 healthy males received acute doses of 10 mg paroxetine, 25 mg amitriptyline, and placebo. The subjects were administered three driving tasks--road tracking, car following, and harsh braking--performed using a driving simulator and three cognitive tasks--Wisconsin Card Sorting Test, Continuous Performance Test, and N-back test at baseline and at 1 h and 4 h post-dosing. The Stanford Sleepiness Scale scores were also assessed.

RESULTS

At 4 h post-dosing, amitriptyline significantly impaired road-tracking and car-following performance, reduced driver vigilance, and caused subjective somnolence. Paroxetine impaired neither driving performance nor cognitive function.

CONCLUSIONS

Acute doses of amitriptyline significantly impaired driving performance in the context of driving on crowded urban roads at relatively low speeds. This setting is important with respect to skills necessary for daily driving and may be difficult to measure in actual driving tests. This simulator-based study replicated the results of previous studies and could be considered complementary to them. This method may enable easy and safe screening of the driving hazard potential of drugs.

SSRIs and cognitive performance in a working sample

BACKGROUND

Studies of the impact of antidepressant use on cognitive performance have frequently been carried out among the elderly or on healthy volunteers. Comparatively little research has considered their impact on a relatively young, working population, particularly within the context of everyday life.

AIMS

To examine any association between SSRI use and cognitive performance, mood and human error at work.

METHODS

SSRI users and controls completed a battery of laboratory based computer tasks measuring mood and cognitive function pre- and post-work at the start and end of a working week. They also completed daily diaries reporting their work performance.

RESULTS

SSRI use was associated with memory impairment: specifically poorer episodic, though not working or semantic memory. Effects of SSRI use on recognition memory seemed to vary according to the underlying psychopathology, while effects on delayed recall were most pronounced among those whose symptoms had not (yet) resolved. There were no detrimental effects on psychomotor speed, attention, mood or perceived human error at work.

CONCLUSIONS

The findings lend support to the SSRIs comparative safety, even among workers, particularly as the symptoms of the underlying psychopathology are successfully addressed. Possible memory impairments may, however, be found in those taking SSRIs.

Biomarkers for the effects of selective serotonin reuptake inhibitors (SSRIs) in healthy subjects

AIMS

Studies of novel centrally acting drugs in healthy volunteers are traditionally concerned with kinetics and tolerability, but useful information may also be obtained from biomarkers of clinical endpoints. This paper provides a systematic overview of CNS-tests used with SSRIs in healthy subjects. A useful biomarker should meet the following requirements: a consistent response across studies and drugs; a clear response of the biomarker to a therapeutic dose; a dose-response relationship; a plausible relationship between biomarker, pharmacology and pathogenesis.

METHODS

These criteria were applied to all individual tests found in studies of selective serotonin reuptake inhibitors (SSRIs), performed in healthy subjects since 1966, identified with a systematic MedLine search. Separate databases were created to evaluate the effects of single or multiple dose SSRI-studies, and for amitriptyline whenever the original report included this antidepressant as a positive control. Doses of the antidepressant were divided into high- and low-dose ranges, relative to a medium range of therapeutic doses. For each test, the drug effects were scored as statistically significant impairment/decrease (-), improvement/increase (+) or no change (=) relative to placebo.

RESULTS

56 single dose studies and 22 multiple dose studies were identified, investigating the effects of 13 different SSRIs on 171 variants of neuropsychological tests, which could be clustered into seven neuropsychological domains. Low single doses of SSRIs generally stimulated tests of attention and memory. High doses tended to impair visual/auditory and visuomotor systems and subjective performance, while showing an acceleration in motor function. The most pronounced effects were observed using tests that measure flicker discrimination (improvement at low doses: 75%, medium doses: 40%, high doses: 43% of studies); REM sleep (inconsistent decrease after medium doses, decrease in 83% of studies after high doses); and EEG recordings, predominantly in alpha (decrease in 60% and 43% of studies after low and medium doses, respectively) and in theta activity (increase in 43% and 33% of studies after medium and high doses, respectively). Amitriptyline generally impaired central nervous system (CNS) functions, which increased with doses. Multiple doses caused less pronounced effects on the reported tests. The most responsive tests to amitriptyline appeared to be EEG alpha and theta, and REM sleep duration.

CONCLUSIONS

SSRIs in healthy subjects appear to cause slight stimulating effects after low doses, which tend to diminish with dose. The most consistent effects were observed with flicker discrimination tests, EEG (alpha and beta bands), REM sleep duration, and subjective effects at higher doses. These effects are small compared with amitriptyline and other CNS-active drugs. Multiple dosing with SSRIs caused even fewer measurable differences from placebo, probably due to adaptive processes. SSRI-effects are best detected with a test battery that is sensitive to general CNS-stimulation, but such tests only comprise a very small portion of the close to 200 different methods that were found in current review.

Psychotropic medication use and accidents, injuries and cognitive failures

BACKGROUND

Psychotropic medication has the potential to impair psychomotor and cognitive function, and several medications have well documented links to increased accident and injury susceptibility. Those developed more recently have many fewer side effects. However, there is little work examining any association between psychotropic medication use and safety within the context of other demographic, health and lifestyle factors.

AIMS

To examine and compare any associations between psychotropic medication use (including benzodiazepines, tricyclics and SSRIs) and accidents, injuries and cognitive failures in a community sample.

METHODS

A postal questionnaire survey was conducted among people selected at random from the electoral registers of Cardiff and Merthyr Tydfil.

RESULTS

Psychotropic medication use was associated with accidents, injuries and cognitive failures, particularly among those who already had higher levels of other risk factors and/or continuing mental health problems.

CONCLUSIONS

The well established associations between accidents and injuries and older psychotropic medications were replicated. SSRIs, however, were relatively safer. The study also highlighted the need to consider any effect of psychotropic medication within the context of both mental health status and other factors.

Antipsychotics and dopamine transporter gene polymorphisms in delirium patients

The main objective of the present study was to determine the relationship between treatment responses of delirium and genetic polymorphisms in the dopamine transporter. The optimal dosages of haloperidol and risperidone in the treatment of delirium were also investigated. Either haloperidol or risperidone was administered to delirium patients, and delirium symptoms were measured daily until remission. Variable number of tandem repeat (VNTR) polymorphisms of the dopamine transporter were determined using the polymerase chain reaction. Among 42 subjects, symptoms of delirium appeared a mean of 9.68 days after hospitalization. A majority of the subjects (83.3%) had the type 10/10 polymorphism. Dosages of haloperidol and risperidone at the day of recovery were 1.67 mg/day (SD = 1.32; range 0.5-2.5 mg/day) and 1.19 mg/day (SD = 1.14; range 0.5-5.0 mg/day), respectively. The mean drug response time was 8.5 days in the haloperidol group and 4.8 days in the risperidone group (no significant difference). The response rates at the 3rd and 7th days after medication did not differ with either the drug group or the dopamine transporter polymorphism. Relatively low doses of risperidone and haloperidol exhibited similar efficacies, and dopamine transporter polymorphisms do not appear to play a major role in the action of antipsychotics on delirium.

Adrenoceptor mechanisms underlying imipramine-induced memory deficits in rats

The post-training administration of tricyclic antidepressant imipramine impairs memory consolidation in the passive avoidance task. The present study investigated the effects of intrahippocampal (i.h.) injection of adrenoceptor agents on imipramine-induced (2-8 microg/rat) amnesia. The administration of the alpha1-adrenoceptor agonist phenylephrine (0.05 microg/rat) and the alpha1-adrenceptor antagonist prazosin (0.5 microg/rat) did not alter the effect of imipramine. The lower doses of phenylephrine (0.005 and 0.015 microg/rat) impaired, while the higher dose of the drug (0.025 and 0.05 microg/rat) improved retention. The effect of phenylephrine was not altered by prazosin (0.5 and 1 microg/rat) pretreatment, although prazosin alone decreased retention latencies. The alpha2-adrenoceptor antagonist yohimbine (0.5 and 1 microg/rat) decreased the response induced by imipramine. However, the alpha2-adrenoceptor agonist clonidine (0.08 microg/rat) did not alter the effect of the drug. Clonidine (0.15 and 0.3 microg/rat) by itself decreased, while yohimbine (1 and 2 microg/rat) increased retention latencies. Yohimbine pretreatment attenuated the effect of clonidine. It is concluded that alpha2-adrenoceptor mechanism(s) may be involved in imipramine-induced impairment of memory.

Residual effects of middle-of-the-night administration of zaleplon and zolpidem on driving ability, memory functions, and psychomotor performance

Thirty healthy volunteers participated in this two-part study. Part 1 was a single-blind, two-period crossover design to determine the effects of a single dose of ethanol (0.03% < BAC < 0.05%) or ethanol-placebo on driving ability, memory, and psychomotor performance. Part 2 was a double-blind, five-period crossover design to measure the effects of a middle-of-the-night administration of zaleplon 10 or 20 mg, zolpidem 10 or 20 mg, or placebo on driving ability 4 hours after administration and memory and psychomotor performance 6 hours after administration. The on-the-road driving test consisted of operating an instrumented automobile over a 100-km highway circuit at a constant speed (95 km/h) while maintaining a steady lateral position between the right lane boundaries. The standard deviation of lateral position (SDLP) was the primary performance parameter of the driving test. The psychomotor and memory test battery consisted of the Word Learning Test, the Critical Tracking Test, the Divided Attention Test, and the Digit Symbol Substitution Test. Data for each part were analyzed separately using ANOVA for crossover designs. Zaleplon 10 and 20 mg did not significantly impair driving ability 4 hours after middle-of-the-night administration. Relative to placebo, after zolpidem 10 mg, SDLP was significantly elevated, but the magnitude of the difference was small and not likely to be of clinical importance. Memory and psychomotor test performance was unaffected after both doses of zaleplon and zolpidem 10 mg. In contrast, zolpidem 20 mg significantly increased SDLP and speed variability. Further, zolpidem 20 mg significantly impaired performance on all psychomotor and memory tests. Finally, driving performance, Digit Symbol Substitution Test, Divided Attention Test, and immediate and delayed free recall of the Word Learning Test were significantly impaired after ethanol. The results show that zaleplon (10 and 20 mg) is a safe hypnotic devoid of next-morning residual impairment when used in the middle of the night.

Drug and ECT treatment of depression in the elderly, 1996-2001: a literature review

A computer-based literature search of all antidepressant and electroconvulsive therapy (ECT) treatment studies published between 1995 and September 2001 was conducted. In addition, a review of published chapters, review articles, and metaanalyses was also conducted. Articles were categorized into those reporting comparative studies, those in which the therapeutic agent was not compared with another, articles about ECT, and review articles. These recent publications support the conclusions from prior reviews that antidepressants and ECT are effective and safe treatments for depressed elderly patients. Differences in efficacy and side effects appear to be slight among the various types of antidepressants. Research studies of depressed elderly increased markedly since 1995 compared with all previous years although more studies are still necessary.

Tricyclic antidepressants and cognitive decline

In this study, we sought to determine the cross-sectional and longitudinal relations of tricyclic antidepressant (TCA) use to cognitive function and cognitive change in a population-based sample of adults (n=1,488). Sociodemographic information, TCA use, and baseline scores on the Mini-Mental State Exam (MMSE) were determined in the initial two waves of the study. At wave 3, participants repeated the MMSE; the prospective relation was assessed for change between waves 2 and 3 (median 11.5 years). These findings failed to support the concept that TCA use is related to concurrent measurable cognitive deficits, and TCA use does not appear to significantly compromise memory over a substantial time span.

Conventional and new antidepressant drugs in the elderly

Depression in the elderly is nowadays a predominant health care problem, mainly due to the progressive aging of the population. It results from psychosocial stress, polypathology, as well as some biochemical changes which occur in the aged brain and can lead to cognitive impairments, increased symptoms from medical illness, higher utilization of health care services and increased rates of suicide and nonsuicide mortality. Therefore, it is very important to make an early diagnosis and a suitable pharmacological treatment, not only for resolving the acute episode, but also for preventing relapse and enhancing the quality of life. Age-related changes in pharmacokinetics and in pharmacodynamics have to be kept into account before prescribing an antidepressant therapy in an old patient. In this paper some of the most important and tolerated drugs in the elderly are reviewed. Tricyclic antidepressants have to be used carefully for their important side effects. Nortriptyline, amytriptiline, clomipramine and desipramine as well, seem to be the best tolerated tricyclics in old people. Second generation antidepressants are preferred for the elderly and those patients with heart disease as they have milder side effects and are less toxic in overdose and include the so called atypicals, such as selective serotonin reuptake inhibitors, serotonin noradrenalene reuptake inhibitors and noradrenaline reuptake inhibitors. Monoamine oxidase (MAO) inhibitors are useful drugs in resistant forms of depression in which the above mentioned drugs have no efficacy; the last generation drugs (reversible MAO inhibitors), such as meclobemide, seem to be very successful. Mood stabilizing drugs are widely used for preventing recurrences of depression and for preventing and treating bipolar illness. They include lithium, which is sometimes used especially to prevent recurrence of depression, even if its use is limited in old patients for its side effects, the anticonvulsants carbamazepine and valproic acid. Putative last generation mood stabilizing drugs include the dihydropyridine L-type calcium channel blockers and the anticonvulsants phenytoin, lamotrigine, gabapentin and topiramate, which have unique mechanisms of action and also merit further systematic study. Psychotherapy is often used as an adjunct to pharmacotherapy, while electroconvulsant therapy is used only in the elderly patients with severe depression, high risk of suicide or drug resistant forms.

Antidepressant drugs in the elderly

1. In this article some of the most important and tolerated drugs in the elderly are reviewed. 2. Tricyclic antidepressants have to be used carefully because of their important side effects. Nortriptyline and desipramine appear to be the best tolerated tricyclics in old people. 3. Second generation antidepressants are preferred for the elderly and those patients with heart disease as they have milder side effects and are less toxic in overdose. 4. MAO inhibitors are useful drugs in resistant forms of depression in which the above mentioned drugs have no efficacy and the last generation drugs (reversible MAO inhibitors), such as moclobemide, seem to be very successful. 5. Lithium is sometimes used especially to prevent recurrence of depression, even if its use is limited in old patients due to its side effects. 6. Psychotherapy is often used as an adjunct to pharmacotherapy, while electroconvulsant therapy is used only in the elderly patients with severe depression, high risk of suicide, or drug-resistant forms.

Nefazodone in major depression: adjunctive benzodiazepine therapy and tolerability

One hundred sixty-six patients suffering from major depressive disorders were treated for 8 weeks with nefazodone in an open study in dosage ranges from 200 to 600 mg. This report focuses primarily on the first week of therapy and on the concomitant use of several benzodiazepines, one of which is not metabolized by the cytochrome system (temazepam). Triazolam response was further evaluated as a function of two nefazodone dosage regimens provided during the first week of therapy, one group receiving nefazodone 200 mg/day for 7 days, and another group receiving nefazodone 200 mg/day for 3 days, followed by 4 days with 400 mg/day. Finally, a comparison of three different nefazodone dosages, the third being 400 mg from day 1 on, was also carried out. Outcome measures included Hamilton Rating Scale for Depression total and the total of the three Hamilton Rating Scale for Depression insomnia items, as well as global improvement, a daily completed sleep questionnaire, and adverse event assessment. A combination of nefazodone with a benzodiazepine (BZ) caused more sedation than nefazodone alone; triazolam, the BZ with the shortest half-life and the highest dependence on the cytochrome 450 system for its metabolism, caused the least amount of sedation, and alprazolam and diazepam, the two daytime benzodiazepines, caused the most sedation. Triazolam caused significant and identical reduction of insomnia in both nefazodone groups. Compared with nefazodone 200 mg given as monotherapy, insomnia was significantly improved--not only by triazolam, but also alprazolam and diazepam, but not temazepam. The addition of nefazodone raised triazolam plasma levels to almost 500%, the plasma level of desmethyl-diazepam 87%, and that of alprazolam 34%. Temazepam plasma levels remained unchanged. When prescribing nefazodone with a benzodiazepine, one should expect an improved sleep pattern initially, but at the cost of clinically relevant daytime sedation. The prediction that temazepam, the only BZ not dependent on the cytochrome mechanism for metabolism, should be the least sedating, and triazolam, because of its cytochromic metabolism interference with nefazodone should be the most sedating, could not be confirmed. In fact, triazolam 0.25 mg capsules seem to be the safest treatment of choice when one has to combine a benzodiazepine with nefazodone in initial stages of therapy, at least of the four benzodiazepines tested in this study.

Nefazodone. A review of its pharmacology and clinical efficacy in the management of major depression

Nefazodone hydrochloride is a phenylpiperazine antidepressant with a mechanism of action that is distinct from those of other currently available drugs. It potently and selectively blocks postsynaptic serotonin (5-hydroxytryptamine; 5-HT) 5-HT2A receptors and moderately inhibits serotonin and noradrenaline (norepinephrine) reuptake. In short term clinical trials of 6 or 8 weeks' duration, nefazodone produced clinical improvements that were significantly greater than those with placebo and similar to those achieved with imipramine, and the selective serotonin reuptake inhibitors (SSRIs) fluoxetine, paroxetine and sertraline. The optimum therapeutic dosage of nefazodone appears to be between 300 and 600 mg/day. Limited long term data suggest that nefazodone is effective in preventing relapse of depression in patients treated for up to 1 year. Analyses of pooled clinical trial results indicate that nefazodone and imipramine produces similar and significant improvements on anxiety- and agitation-related rating scales compared with placebo in patients with major depression. Short term tolerability data indicate that nefazodone has a lower incidence of adverse anticholinergic, antihistaminergic and adrenergic effects than imipramine. Compared with SSRIs, nefazodone causes fewer activating symptoms, adverse gastrointestinal effects (nausea, diarrhoea, anorexia) and adverse effects on sexual function, but is associated with more dizziness, dry mouth, constipation, visual disturbances and confusion. Available data also suggest that nefazodone is not associated with abnormal weight gain, seizures, priapism or significant sleep disruption, and appears to be relatively safe in overdosage. Nefazodone inhibits the cytochrome P450 3A4 isoenzyme and thus has the potential to interact with a number of drugs. Further long term and comparative studies will provide a more accurate assessment of the relative place of nefazodone in the management of major depression. Nonetheless, available data suggest that nefazodone is a worthwhile treatment alternative to tricyclic antidepressants and SSRIs in patients with major depression.

A study of the effect of age and gender on the pharmacokinetics of nefazodone after single and multiple doses

The single-dose (S-D) and steady-state (S-S) pharmacokinetics of nefazodone (NEF) and two of its pharmacologically active metabolites, hydroxynefazodone (HO-NEF) and m-chlorophenylpiperazine (mCPP), in healthy elderly (> 65 years) men and women (N = 12 each) were compared with those in healthy younger (18-40 years) men and women (N = 12 each). All subjects were classified as extensive metabolizers of dextromethorphan (cytochrome P4502D6). Subjects were administered a 300-mg dose of nefazodone hydrochloride for the evaluation of S-D pharmacokinetics. For the evaluation of S-S pharmacokinetics, 300-mg doses of NEF were administered twice daily (every 12 hours) for 8 days (single morning dose on day 8). Serial blood samples were collected after the single dose and the morning dose on day 8 of the twice-daily administration; a blood sample for trough level was collected from each subject just before the morning dose on days 2 to 8 of the twice-daily dosing to assess the attainment of steady state. Plasma samples were assayed for NEF, HO-NEF, and mCPP by a specific, validated high-performance liquid chromatography assay. After a single dose of NEF, the mean peak concentrations in plasma and the area under the curves (AUC) for NEF and HO-NEF were about twofold higher in elderly versus young subjects, but mean AUCs for mCPP were similar. Levels in plasma for NEF, HO-NEF, and mCPP reached steady state by day 3 of multiple dosing. At steady state, exposure to NEF and HO-NEF, based on AUC(TAU) values, was quite variable among age/gender groups but on the average was about 50% higher in elderly women compared with the other three groups of subjects; the exposure to mCPP at steady state was similar in elderly and young subjects. Because all subjects were extensive metabolizers, the effect of gender or age on the pharmacokinetics of NEF and its metabolites in poor metabolizers is not known. There were no serious or unexpected adverse experiences observed in this study. Assuming that similar systemic exposure to NEF and its active metabolites will result in similar therapeutic effects in young and elderly individuals, the difference in systematic exposure to NEF and HO-NEF in elderly subjects suggests that NEF treatment should be initiated at half the usual dose with titration upward and that the usual precautions exercised in treating elderly patients should be used.

Investigation of pharmacokinetic and pharmacodynamic interactions after coadministration of nefazodone and haloperidol

A double-blind, placebo-controlled study using 12 healthy men was designed to evaluate pharmacokinetic and pharmacodynamic interactions when nefazodone and haloperidol are coadministered. Two groups of six subjects each received a 5-mg oral dose of haloperidol or a placebo on study days 1 and 2. Nefazodone, 200 mg, was administered to all 12 subjects twice daily (every 12 hours) on study days 3 to 9; on study day 10, only the morning dose of nefazodone was administered. On study days 9 and 10, all subjects also received 5 mg of haloperidol or a placebo along with the morning dose of nefazodone. Serial blood samples for pharmacokinetic analysis were collected from each subject over a 12-hour period after the morning dose on study days 1, 2, 9, and 10. Plasma samples were assayed for haloperidol, reduced haloperidol, nefazodone, hydroxynefazodone and m-chlorophenylpiperazine by specific, validated high-performance liquid chromatogoraphy methods. Psychomotor performance tests to evaluate haloperidol pharmacodynamics were also performed on days 1, 2, 9, and 10. Reduced haloperidol in the majority of samples was below the limit of quantitation; therefore, the effect of nefazodone on the pharmacokinetics of reduced haloperidol could not be determined. The administration of 5 mg of haloperidol to subjects dosed with nefazodone to steady state led to a modest pharmacokinetic interaction, as indicated by a 36, 13, and 37% increase in mean area under the curve (AUC0-12), highest concentration, and 12-h concentration values for haloperidol, respectively; only the increase in AUC was statistically significant. In contrast, the steady-state pharmacokinetics of nefazodone, hydroxynefazodone, and m-chlorophenylpiperazine were not affected by the administration of haloperidol. Although there were significant differences observed in some psychomotor performance tests, the effects of nefazodone on the pharmacodynamics of haloperidol could not be consistently demonstrated. The results from this study suggest that nefazodone has only modest pharmacokinetic and pharmacodynamic interactions with haloperidol. Although no specific recommendations can be made, dosage adjustment may be necessary for haloperidol when coadministered with nefazodone.

Safety, tolerance, and preliminary pharmacokinetics of nefazodone after administration of single and multiple oral doses to healthy adult male volunteers: a double-blind, phase I study

Safety, tolerance, and preliminary pharmacokinetics of nefazodone, a new antidepressant, were assessed in a randomized, double-blind, parallel group study carried out in two sequential segments: a single and a multiple daily dose segment. Nine subjects in the single daily dose segment were divided into three treatment groups and received nefazodone doses in a leapfrog fashion. Each day of treatment with nefazodone was followed by 2 days of placebo treatment and then administration of the next higher drug dose. Single doses ranged from 5-500 mg. 8 subjects enrolled in the multiple daily dose segment were divided into two treatment groups. In each group, 3 subjects received nefazodone and one received placebo 3 times a day. Each dosage level was administered for 2 days before proceeding to the next higher dose from 5 mg or 10 mg 3 times a day to a maximum of 500 mg 3 times a day. After the dose-escalation period, the subjects in the multiple daily dose segment underwent a 3-day washout, after which they received a single dose of nefazodone at the maximum tolerated level. Safety and tolerance assessment involved analyses of adverse events, laboratory tests, vital signs, ophthalmic examinations, and ECGs. Blood and urine samples were obtained only in the multiple daily dose segment and analyzed for nefazodone and its two pharmacologically active metabolites, hydroxynefazodone and mCPP. A single blood sample was collected on 8 different days for assessment of trough levels (Cmin) and serial samples were obtained on days 5, 9, and 22 of dosing for pharmacokinetic profiles. Additional serial samples were also obtained after the last single dose of 500 mg after a 3-day washout. Nefazodone was found to be safe and well-tolerated in total daily doses as high as 1350 mg (450 mg 3 times a day). Nefazodone was rapidly absorbed after oral administration and converted to hydroxynefazodone and mCPP. The pharmacokinetics of nefazodone, hydroxynefazodone, and mCPP were found to be dose-dependent, as evidenced by dose normalized values of Cmin, Cmax, and AUC0-8 that progressively increased with dose. Although exposure of normal subjects to nefazodone and its 2 pharmacologically active metabolites was disproportionately higher than the corresponding increase in dose, the safety and tolerance profiles did not show a parallel increase in adverse events. Nefazodone may be well-tolerated by patients receiving expected therapeutic doses from 200-600 mg per day when administered in divided doses every 8 to 12 hours.

Nonlinear pharmacokinetics of nefazodone after escalating single and multiple oral doses

The single- and multiple-dose pharmacokinetics of nefazodone and its metabolites, hydroxynefazodone, p-hydroxynefazodone, and m-chlorophenylpiperazine were investigated in two groups of 18 healthy male volunteers, employing three-period complete crossover designs. In one group, single 50-mg, 100-mg, and 200-mg oral doses of nefazodone hydrochloride were administered with a 1-week washout between treatments. In the other group, doses of 50 mg, 100 mg, and 200 mg were administered twice a day (every 12 hours) for 7.5 days (15 doses) with a 1-week washout between treatments. Serial plasma samples were obtained in both groups and assayed for nefazodone, hydroxynefazodone, m-chlorophenylpiperazine, and p-hydroxynefazodone. Cmax plasma levels of nefazodone and hydroxynefazodone were attained within 2 hours of administration of nefazodone; tmax for m-chlorophenylpiperazine was more delayed, and p-hydroxynefazodone levels were generally below the assay limit. On repeated twice-daily dosing of nefazodone, steady-state levels of the drug and its metabolites were reached within 3 days. Mean single-dose plasma half-life (t1/2) values for nefazodone increased from approximately 1 hour at a 50-mg dose to approximately 2 hours at a 200-mg dose; at steady state, t1/2 values increased from approximately 2 hours at 50 mg twice daily to approximately 3.7 hours at 200 mg twice daily. Whereas dose increased in the proportion of 1:2:4, mean single-dose AUC0-infinity for nefazodone increased in the proportion of 1:3.3:8.9 and mean steady-state AUC0-tau for nefazodone increased in the proportion of 1:4.2:16.8. Plasma levels of hydroxynefazodone paralleled those of nefazodone and were approximately 33% of nefazodone levels at each dose level. Plasma levels of m-chlorophenylpiperazine were only approximately 10% those of nefazodone. Within the dosage range of 50-200 mg of nefazodone hydrochloride, nefazodone and hydroxynefazodone exhibited nonlinear pharmacokinetics; m-chlorophenylpiperazine, a minor metabolite, appeared to exhibit linear pharmacokinetics.