Actions of zopiclone and carbamazepine, alone and in combination, on human skilled performance in laboratory and clinical tests

Zopiclone's residual effects on psychomotor and information processing skills involved in complex tasks such as car driving: a critical review

Before and after its introduction in 1987, zopiclone was the object of investigation in 16 psychometric studies employing both healthy volunteers and insomniac patients. Their common purpose was to determine whether nocturnal doses (usually the standard 7.5 mg) possess residual sedative effects that interfere with skilled safety-relevant performance, such as car driving, over the following day. Most studies have found no residual effects. Those that did, have shown them to be modest in magnitude and not to persist for longer than about 12 hours from the time of dosage. Without altering the general conclusion that zopiclone possesses few if any residual effects of clinical relevance, it must be said that the studies reviewed failed to meet current methodological standards and may have left some important questions unanswered.

Orexin receptor antagonists differ from standard sleep drugs by promoting sleep at doses that do not disrupt cognition

Current treatments for insomnia, such as zolpidem (Ambien) and eszopiclone (Lunesta), are γ-aminobutyric acid type A (GABAA)-positive allosteric modulators that carry a number of side effects including the potential to disrupt cognition. In an effort to develop better tolerated medicines, we have identified dual orexin 1 and 2 receptor antagonists (DORAs), which promote sleep in preclinical animal models and humans. We compare the effects of orally administered eszopiclone, zolpidem, and diazepam to the dual orexin receptor antagonist DORA-22 on sleep and the novel object recognition test in rat, and on sleep and two cognition tests (delayed match to sample and serial choice reaction time) in the rhesus monkey. Each compound's minimal dose that promoted sleep versus the minimal dose that exerted deficits in these cognitive tests was determined, and a therapeutic margin was established. We found that DORA-22 has a wider therapeutic margin for sleep versus cognitive impairment in rat and rhesus monkey compared to the other compounds tested. These data were further supported with the demonstration of a wider therapeutic margin for DORA-22 compared to the other compounds on sleep versus the expression of hippocampal activity-regulated cytoskeletal-associated protein (Arc), an immediate-early gene product involved in synaptic plasticity. These findings suggest that DORAs might provide an effective treatment for insomnia with a greater therapeutic margin for sleep versus cognitive disturbances compared to the GABAA-positive allosteric modulators currently in use.

Individual psychomotor impairment in relation to zopiclone and ethanol concentrations in blood--a randomized controlled double-blinded trial

AIMS

To investigate individual traffic-relevant impairment related to measured blood zopiclone and ethanol concentrations. Also, we aimed to study possible development of acute tolerance.

DESIGN

A randomized controlled four-way cross-over double-blind trial. Study drugs were zopiclone 5 or 10 mg, 50 g ethanol or placebo.

SETTING

Laboratory study with computerized tests: Connor's Continuous Performance test, Choice Reaction Time and Stockings of Cambridge. Altogether, the tests consisted of 15 test components, representing three levels of behaviour (automotive, control, executive planning), relevant to traffic safety.

PARTICIPANTS

Sixteen healthy male volunteers.

MEASUREMENTS

Each study day, 10 blood samples were collected from each volunteer. Fifteen psychomotor test components were registered at baseline and a further three times after intake. Impairment was defined as any individual deterioration in performance compared to individual baseline performance.

FINDINGS

Blood drug concentrations up to 74 µg/l zopiclone and 0.100% ethanol were measured. We found a clear positive concentration-effect relationship for zopiclone and ethanol for both automotive and control behaviours, and a modest relationship for executive planning behaviour. Significant impairment started to be observed at concentrations above 16 µg/l zopiclone (automotive and control behaviour) and above 0.026% ethanol (automotive behaviour). Acute tolerance was found for both drugs.

CONCLUSIONS

The hypnotic, zopiclone, can impair psychomotor performance at blood concentrations as low as 16 µg/l.

Impairment related to blood drug concentrations of zopiclone and zolpidem compared to alcohol in apprehended drivers

BACKGROUND

About 3-7% of the adult population receives prescribed hypnotics. The benzodiazepine-like hypnotics, zopiclone and zolpidem, are the most commonly prescribed and may cause traffic-relevant impairment similar to that found for benzodiazepines. We investigated the relationship between blood zopiclone and zolpidem concentrations and driving impairment, as assessed by the clinical test for impairment. We compared these groups of drivers to a group suspected of alcohol-related impairment.

METHODS

Blood samples from suspected impaired drivers during 2000-2007, screened for approximately 25 possible impairing drugs with only one single drug detected, were studied in relation to the assessment of impairment. The 79 zopiclone positive drivers, the 43 zolpidem positive drivers, and the 3480 alcohol positive drivers were divided into groups depending on blood drug concentrations.

RESULTS/DISCUSSION

The proportion of drivers judged as impaired tended to increase the higher the blood zopiclone concentrations. Such a positive relationship was not found for zolpidem. For alcohol the proportion of impaired drivers was significantly related to blood alcohol concentrations (BACs). There were few drivers with low zopiclone or zolpidem concentrations included, which may have obscured any positive significant relationship. The percentage of impaired drivers among drivers with blood zopiclone concentrations above 130 microg/l roughly corresponded to the percentage of impaired drivers among drivers with BACs higher than 0.1%.

Clinical use of carbamazepine for bipolar disorders

Two recently completed large, randomised, double-blind, placebo-controlled trials supporting the efficacy of carbamazepine (CBZ) extended-release capsules (ERC) for the treatment of acute manic and mixed episodes have resulted in US FDA approval of CBZ-ERC, and have reinvigorated the importance of understanding the role of CBZ in bipolar disorder (BD) pharmacotherapy. Additional data suggest that CBZ may have a use in BD maintenance treatment and possibly in acute BD depression. Optimal use of CBZ requires sound knowledge of adverse effects and pharmacokinetic interactions with this agent. Adverse effects commonly involve benign side effects but can rarely include serious haematological, dermatological and hepatic manifestations. On the other hand, metabolic adverse effects (thyroid, glucose, lipid disturbances and significant weight gain) can be less problematic with CBZ, compared with lithium, valproate and atypical antipsychotics. Pharmacokinetic considerations (cytochrome P450 3A3/4 metabolism, active epoxide metabolite and catabolic enzyme induction) can influence the clinical use of CBZ. Managing adverse effects and pharmacokinetic complexities is important for optimising pharmacotherapy with CBZ in patients with BD. This paper reviews the chemistry, pharmacodynamics and pharmacokinetics of CBZ, as well as reviews of the controlled trials of CBZ in acute bipolar mania, acute bipolar depression and bipolar maintenance treatment.

Testing for benzodiazepine inebriation--relationship between benzodiazepine concentration and simple clinical tests for impairment in a sample of drugged drivers

OBJECTIVE

To study how the various 25 subtests and observations of the Norwegian clinical test for impairment related to the blood benzodiazepine concentrations of apprehended drivers suspected of driving under the influence of benzodiazepines. The impact of single-dose intake in non-daily users of benzodiazepines on the clinical picture of inebriation was also studied.

METHODS

Included in the study were 818 drivers suspected of driving under the influence of non-alcoholic drugs with blood samples containing only one benzodiazepine. We determined which of the 25 subtests and observations of the clinical test for impairment related significantly to the blood benzodiazepine concentrations.

RESULTS

Significantly related to blood benzodiazepine concentrations were 13 subtests and observations. Of these, 9 withstood adjustment for a variety of background variables. Single dose intake in non-daily users only influenced 3 subtests and observations after adjustment for blood benzodiazepine concentration and background variables. Romberg's test, 1 observation concerning alertness (oriented for time and place), 4 tests on motor and coordination (walk and turn on line, finger-to-nose and finger-to-finger tests), 2 observations on speech (articulation and content) and 1 observation regarding appearance (general conduct) were related to blood benzodiazepine concentrations.

CONCLUSION

Many of these simple clinical tests are included in the standardized field sobriety test and are of value in revealing benzodiazepine impairment. The present study offered some possible additions. Combinations of these robust tests can also be used to reveal benzodiazepine inebriation in other contexts.

The psychomotor effects of carbamazepine in epileptic patients and healthy volunteers

The effect of straight release carbamazepine monotherapy was studied in 12 well-controlled epileptic patients using adaptive tracking, smooth pursuit and saccadic eye movements, body sway, Digit Symbol Substitution Test (DSST) and Visual Analogue Scales. Patients were matched to healthy controls for age and gender. After patients had received their usual morning dose of carbamazepine, patient-control pairs were studied for 7 h. Compared to controls, the average DSST scores of patients were significant lower. No relationships were shown between DSST performance and plasma concentrations of carbamazepine and carbamazepine-epoxide. No significant differences were found for any of the other effect parameters. Variations in plasma concentrations were limited, contributing to the absence of systematic fluctuations in test results. Of the used tests, DSST is most clearly related to cognitive function. It is concluded that the difference in DSST performance appears to reflect a long-term small neurocognitive difference between subjects with and without epilepsy.

Clinically important drug interactions with zopiclone, zolpidem and zaleplon

Insomnia, an inability to initiate or maintain sleep, affects approximately one-third of the American population. Conventional benzodiazepines, such as triazolam and midazolam, were the treatment of choice for short-term insomnia for many years but are associated with adverse effects such as rebound insomnia, withdrawal and dependency. The newer hypnosedatives include zolpidem, zaleplon and zopiclone. These agents may be preferred over conventional benzodiazepines to treat short-term insomnia because they may be less likely to cause significant rebound insomnia or tolerance and are as efficacious as the conventional benzodiazepines. This review aims to summarise the published clinical drug interaction studies involving zolpidem, zaleplon and zopiclone. The pharmacokinetic and pharmacodynamic interactions that may be clinically important are highlighted. Clinical trials have studied potential interactions of zaleplon, zolpidem and zopiclone with the following types of drugs: cytochrome P450 (CYP) inducers (rifampicin), CYP inhibitors (azoles, ritonavir and erythromycin), histamine H(2) receptor antagonists (cimetidine and ranitidine), antidepressants, antipsychotics, antagonists of benzodiazepines and drugs causing sedation. Rifampicin significantly induced the metabolism of the newer hypnosedatives and decreased their sedative effects, indicating that a dose increase of these agents may be necessary when they are administered with rifampicin. Ketoconazole, erythromycin and cimetidine inhibited the metabolism of the newer hypnosedatives and enhanced their sedative effects, suggesting that a dose reduction may be required. Addition of ethanol to treatment with the newer hypnosedatives resulted in additive sedative effects without altering the pharmacokinetic parameters of the drugs. Compared with some of the conventional benzodiazepines, fewer clinically important interactions appear to have been reported in the literature with zaleplon, zolpidem and zopiclone. The fact that these drugs are newer to the market and have not been as extensively studied as the conventional benzodiazepines may be the reason for this. Another explanation may be a difference in CYP metabolism. While triazolam and midazolam are biotransformed almost entirely via CYP3A4, the newer hypnosedatives are biotransformed by several CYP isozymes in addition to CYP3A4, resulting in CYP3A4 inhibitors and inducers having a lesser effect on their biotransformation.

Clinical impairment of benzodiazepines--relation between benzodiazepine concentrations and impairment in apprehended drivers

BACKGROUND

Acute intake of benzodiazepines is followed by concentration-dependent deterioration of performance in controlled experimental studies. Whether this is true in a population of benzodiazepine users is uncertain. We studied the relationship in a population of suspected drugged drivers.

METHODS

In Norway physicians examine and take blood samples from nearly all suspected drivers. Our material comprised 818 samples containing only one benzodiazepine and our reference group consisted of 10,759 cases containing only alcohol.

RESULTS

159 drivers (19%) were considered as not impaired and 659 (81%) as impaired. None of the background factors, e.g. gender, age or time of day when apprehended, related significantly to either the physician's conclusion or to blood levels of benzodiazepines. Impaired subjects had significantly higher blood levels of diazepam (n=411) (P<0.001), oxazepam (n=73) (P<0.05) and flunitrazepam (n=211) (P<0.05) than those not impaired. The risk of being assessed as impaired did rise with increasing benzodiazepine blood level, with odds ratios (ORs) for being assessed as impaired of 1.61, 3.65 and 4.11 for the three supratherapeutic drug levels. The corresponding OR found for different elevated blood-alcohol concentrations were 1.49, 2.94 and 10.49.

CONCLUSION

The blood concentration of benzodiazepines was the only characteristic which was related to impairment. This indicated a drug-concentration related effect of benzodiazepines on performance and paves the way for a discussion on legal limits for benzodiazepines in relation to driving.

Effects of alcohol, zolpidem, and some other sedatives and hypnotics on human performance and memory

Zolpidem (Zol), an omega1-agonist, acts via GABA(A) receptors but may differ qualitatively from diazepam (Dz) and other benzodiazepines (BZDs). We conducted a placebo-controlled, randomized, double-blind, and crossover study to compare the psychomotor and cognitive effects of 15 mg Zol with those of 15 mg Dz, 30 mg oxazepam (Ox), 7.5 mg zopiclone (Zop), and ethanol (EOH; 0.65 + 0.35 g x kg(-1)) given to 12 subjects at 1-week intervals. Psychomotor tests (symbol digit substitution, simulated driving, flicker fusion, body sway) were done before and 1, 3.5, and 5 h after intake; immediate and delayed memory were measured between 1.5 and 3.5 h. The plasma concentrations of drugs were measured by gas chromatography and by radioreceptor assay (RRA). The mean values of EOH in blood at 1.5, 4, and 5.5 h were 0.82, 0.88, and 0.6 g x l(-1), and the mean values of RRA-assayed plasma Dz were 470, 330, and 210 microg x l(-1), respectively. The corresponding values of other hypnosedatives, in Dz equivalents (microg x l(-1)), were 550, 750, and 330 for Ox; 350, 270, and 70 for Zol; and 160, 210, and 70 for Zop. The standard RRA graph for Zol was significantly flatter than those for other hypnotics. Zol impaired coordinative, reactive, and cognitive skills at 1 and 3.5 h more clearly than the other agents did, the most sensitive performance (tracking) still being impaired by Zol at 5 h. Dz and Zop were less active than Zol objectively; subjective sedation after Dz and Zol was stronger than after Zop. Compared to placebo, all active agents tended to impair learning and memory, their decremental effects, in declining order, being Zol, Dz > EOH, Ox > Zop. During the delay, Dz and Zol caused similar losses of material that had been learned. When separating "true" delayed memory from immediate memory (attention important), Dz and Zol had equieffects on delayed memory and were more detrimental than Zop. When contrasting that against the impaired psychomotor performances, it is possible that 15 mg Zol impairs memory relatively less than 15 mg Dz does.

Zopiclone. An update of its pharmacology, clinical efficacy and tolerability in the treatment of insomnia

Zopiclone is a non-benzodiazepine hypnotic which was first reviewed in Drugs in 1986. At that time, zopiclone had shown hypnotic efficacy superior to that of placebo, but had not been extensively compared with benzodiazepine hypnotics in patients with insomnia. A much larger body of clinical data is now available, allowing a more detailed evaluation than was previously possible. Together with results from earlier studies, subsequent clinical trials have shown that zopiclone is generally at least as effective as the benzodiazepines (regardless of duration of action) in the treatment of insomnia, although comparisons between zopiclone and flurazepam have produced inconsistent results. Tolerance to the effects of zopiclone was not seen in short term clinical trials (< or = 4 weeks); data from longer term studies are conflicting and the potential for tolerance during long term zopiclone treatment is therefore unclear. Zopiclone has a relatively low propensity to cause residual clinical effects (such as difficulty in waking or reduced morning concentration). Rebound of insomnia to a level below that at baseline can occur after withdrawal of zopiclone, but, on the basis of data from short term studies, does not appear to be common. Data from prescription-event monitoring suggest that zopiclone does not have a high dependence potential (at least in those who are not regular drug abusers/addicts). Zopiclone is well tolerated in both the elderly and younger patients with insomnia. A bitter aftertaste is usually the most common adverse event, but is relatively infrequent (3.6% in the largest available postmarketing study). Thus, zopiclone is now firmly established as an effective and well tolerated hypnotic agent. Although the available data on rebound insomnia and dependence liability are encouraging, potential differences between zopiclone and the benzodiazepines in these respects may have little clinical relevance in the context of short term intermittent use of hypnotics, as it currently recommended. A low propensity for rebound insomnia and dependence might prove valuable during long term hypnotic therapy (which, although not recommended, is a clinical reality). However, the risk-benefit profile of zopiclone in this context remains unknown. Nevertheless, zopiclone is clearly a suitable alternative to the benzodiazepines for the short term treatment of insomnia.

Clinical management of patients with insomnia. The role of zopiclone

Insomnia, especially when chronic, is associated with disturbances in daytime well-being and performance, resulting in a poor quality of life for those affected. Zopiclone has been proven as a drug that favourably balances sleep induction and maintenance as well as an improvement in daytime well-being (efficacy) with a low potential for adverse effects (safety) in the symptomatic treatment of insomnia. Management of chronic insomnia with zopiclone needs a multidimensional approach involving the proper diagnosis of possible underlying causes, and combined use of causal treatment, general sleep hygiene measures, basic elements of psychological treatment and adjunctive medication. It is recommended that therapy with the nonbenzodiazepine hypnotic zopiclone should conform to the guidelines for the use of hypnotics, which are valid for all benzodiazepine receptor agonists.

Clinical pharmacokinetics of zopiclone

Zopiclone is a cyclopyrrolone hypnotic agent. It possesses a chiral centre and is commercially available as a racemic mixture. Methods involving high performance liquid chromatography (HPLC), gas chromatography, capillary electrophoresis (CE) and high performance thin layer chromatography have been developed for the quantitation of zopiclone and its 2 main metabolites in biological samples. For the chiral determination of the enantiomers of zopiclone and its metabolites, HPLC and CE methods are available. After oral administration, zopiclone is rapidly absorbed, with a bioavailability of approximately 80%. The plasma protein binding of zopiclone has been reported to be between 45 and 80%. Zopiclone is rapidly and widely distributed to body tissues including the brain, and is excreted in urine, saliva and breast milk. Zopiclone is partly metabolised in the liver to form an inactive N-demethylated derivative and an active N-oxide metabolite. In addition, approximately 50% of the administered dose is decarboxylated and excreted via the lungs. Less than 7% of the administered dose is renally excreted as unchanged zopiclone. In urine, the N-demethyl and N-oxide metabolites account for 30% of the initial dose. The terminal elimination half-life (t1/2z) of zopiclone ranges from 3.5 to 6.5 hours. The pharmacokinetics of zopiclone in humans are stereoselective. After oral administration of the racemic mixture, Cmax (time to maximum plasma concentration), AUC (area under the plasma time-concentration curve) and t1/2z values are higher for the dextrorotatory enantiomer owing to the slower total clearance and smaller volume of distribution (corrected by the bioavailability), compared with the levorotatory enantiomer. In urine, the concentrations of the dextrorotatory enantiomers of the N-demethyl and N-oxide metabolites are higher than those of the respective antipodes. The pharmacokinetics of zopiclone are altered by aging and are influenced by renal and hepatic functions. Drug interactions have been observed with erythromycin, trimipramine and carbamazepine.

Lorazepam and diazepam differently impair divided attention

Effects of ethanol (EtOH, 0.65 + 0.35 g.kg-1), diazepam (DZ, 15 and 30 mg), lorazepam (LZ, 2 mg) on divided attention were measured in two placebo-controlled crossover studies with healthy young subjects. The test comprised four parallel computer screens with a ball moving along a circular obstacle course on each screen at different rates. When the ball entered an obstacle on any screen, the subject had to press the respective button. The obstacles varied in numbers and shapes, and randomly changed their location every 10 s. Concomitant aural stimuli were responded to by pushing the foot pedals. The primary visual variables were the absolute and percent numbers of correct responses on each screen. Concentrated attention was measured with a symbol digit substitution (SDST) and digit copying (DDCT) tests, for 3 min each. In Study I, with 12 subjects, the tests (4 min) were made before the treatment (placebo, EtOH, DZ) and 1, 3, and 6 h after intake. EtOH impaired attention on the lateral but not on medial screens, with and without aural stimuli, the "special" obstacles of deviating shape being the most sensitive targets to EtOH effects. DZ 15 mg did not modify divided attention whereas it impaired SDST performance and was subjectively slightly more potent than EtOH on visual analog scales. DZ 30 mg impaired attention on the lateral screens, with and without aural stimuli, but without preference to "special" obstacles. It also reduced responses to aural stimuli, strongly impaired SDST and DDCT, and caused subjective sedation. In Study II, with 9 subjects, the test run without aural stimuli was easier but lasted for 15 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug and ethanol effects on the clinical test for drunkenness: single doses of ethanol, hypnotic drugs and antidepressant drugs

The clinical test for drunkenness has been used in Finland to detect alcohol-induced impairment of driving fitness. Since the data about the effects of psychotropic drugs on the clinical test for drunkenness are limited, this test was administered in two randomized double-blind cross-over trials with 12 subjects in each. The clinical tests were done at 2 hr and 5 hr after drug intake. For comparison, the representative laboratory tests used were digit symbol substitution, simulated driving (tracking+reaction time) and "global psychomotor performance". In Trial I, 15 mg of diazepam, 50 mg of amitriptyline and 15 mg of mirtazepine, each drug administered alone, had minor effects on the clinical tests. Compared to the placebo, mirtazepine, and diazepam, diazepam+mirtazepine impaired performance on the motor subtests at 2 hr. The tracking error percentage was increased by amitriptyline, diazepam+amitriptyline, and diazepam+mirtazepine up to 4.5 hr. In Trial II with 7.5 mg of zopiclone, 0.25 mg of triazolam and 0.8 g/kg of ethanol, ethanol alone and hypnotic-ethanol combinations impaired performance on the motor and vestibular subtests, whereas single drug intake had minor effects. Tracking was more sensitive to drugs than to ethanol. In conclusion, the clinical test for drunkenness detected impaired performance following single doses of ethanol or drug-ethanol combinations better than it detected impaired performance following moderate doses of drugs or drug-drug combinations, respectively.

Suriclone enhances the actions of chlorpromazine on human psychomotor performance but not on memory or plasma prolactin in healthy subjects

Twelve healthy subjects received single oral doses of 0.4 mg suriclone (SU), 7.5 mg zopiclone (ZO) and placebo, alone and together with 50 mg chlorpromazine (CP), double blind and crossover, in Latin square order, at one-week intervals. Performance tests administered before and 1.5, 3.5 and 6 h after drug intake included digit symbol substitution and simulated driving combined in a "Global test", flicker fusion frequency, body balance and memory and subjective assessments. Changes from baseline were examined statistically. Performance and memory data were analysed from only 11 subjects. Compared to placebo, SU minimally affected "global" performance, although it slowed reactions and tended to impair digit substitution. ZO impaired "global" performance at 1.5 h, affected performance in several separate tests, and produced subjective muzziness. CP did not impair "global" performance, although it did impair digit substitution and render the subjects drowsy, weak and dreamy. The combinations SU + CP and ZO + CP definitely impaired "global" performance more than CP alone. This difference was also found in most objective tests but less so in the subjective tests. CP and its combinations produced similar increases in plasma prolactin. Active drugs and their combinations variably lowered blood pressure and increased heart rate, and one subject collapsed after CP. The treatments irregularly impaired spatial memory and learning acquisition. No pharmacokinetic interactions were seen in the plasma levels of suriclone, zopiclone and chlorpromazine. The impairment of performance after these combinations resembles that previously encountered after 2.5 mg lorazepam, or 15 mg diazepam + 100 mg remoxipride.

Zopiclone. A review of its pharmacological properties and therapeutic efficacy as an hypnotic

Zopiclone is a cyclopyrrolone which is chemically unrelated to the benzodiazepines and is thought to act on the GABAA receptor complex at a site distinct from, but closely related to, the benzodiazepine binding site. The hypnotic efficacy of zopiclone administered as single oral doses has been demonstrated in patients undergoing next-day surgery and in patients with insomnia, and these studies have established an optimal dose of 7.5mg for elderly patients. Using this dose, clinical studies have shown that zopiclone improved sleep in elderly patients to a similar extent as triazolam 0.125 to 0.5mg, flurazepam 15mg, and nitrazepam 5mg. Studies that also included younger patients have shown that zopiclone 7.5mg is at least as effective as triazolam 0.25 or 0.5mg, and on most sleep parameters is comparable to temazepam 20mg, nitrazepam 5mg, flunitrazepam 2mg, and flurazepam 20mg. Zopiclone causes minimal impairment to psychomotor performance and mental alertness the morning after night-time administration. The drug is generally well tolerated by patients of all ages; the most frequently reported adverse effects being bitter taste and dry mouth. Treatment withdrawal due to adverse effects is seldom required and reports of rebound insomnia after zopiclone withdrawal are rare. While symptoms of physical dependence have not been observed in clinical studies, there have been isolated reports of physical dependence in patients with a history of substance abuse. Although the latter finding should be kept in mind, it appears that zopiclone has a low dependence liability. Thus, with its short duration of action and good tolerability profile, zopiclone is a well established alternative to the benzodiazepine hypnotics and may be particularly beneficial in those patients unable or unwilling to tolerate the residual effects associated with many other hypnotic agents.

The use of microcomputer-based psychomotor tests for the evaluation of benzodiazepine effects on human performance: a review with emphasis on temazepam

1. The literature relating to the effects of benzodiazepines in general, and temazepam in particular, on human psychomotor performance as assessed using microcomputer-based testing batteries is surveyed. 2. The adverse effects of central nervous system depressants on performance is an important mediocolegal issue and frequently comes into question in on-the-road and on-the-job accidents. The use of microcomputer-based testing batteries allows for performance evaluation both in the laboratory and at-the-scene, as well as providing the opportunity to model a large number of different behaviours required in routine yet complex psychomotor tasks. 3. The conclusions in general are: (1) The benzodiazepines as a class of drugs impair both cognitive and motor performance. These effects are often subtle when low doses are involved or when testing occurs the morning following evening administration of the medication. (2) No single psychomotor task adequately simulates complex daily tasks such as automobile driving. A battery of tests that evaluates a number of the components of such tasks is necessary to determine adequately the full range of effects of these medications.