Psychomotor effects of alprazolam and diazepam during acute and subacute treatment, and during the follow-up phase

The Effect of Chronic Alprazolam Intake on Memory, Attention, and Psychomotor Performance in Healthy Human Male Volunteers

Alprazolam is used as an anxiolytic drug for generalized anxiety disorder and it has been reported to produce sedation and anterograde amnesia. In the current study, we randomly divided 26 healthy male volunteers into two groups: one group taking alprazolam 0.5 mg and the other taking placebo daily for two weeks. We utilized the Cambridge Neuropsychological Test Automated Battery (CANTAB) software to assess the chronic effect of alprazolam. We selected Paired Associates Learning (PAL) and Delayed Matching to Sample (DMS) tests for memory, Rapid Visual Information Processing (RVP) for attention, and Choice Reaction Time (CRT) for psychomotor performance twice: before starting the treatment and after the completion of the treatment. We found statistically significant impairment of visual memory in one parameter of PAL and three parameters of DMS in alprazolam group. The PAL mean trial to success and total correct matching in 0-second delay, 4-second delay, and all delay situation of DMS were impaired in alprazolam group. RVP total hits after two weeks of alprazolam treatment were improved in alprazolam group. But such differences were not observed in placebo group. In our study, we found that chronic administration of alprazolam affects memory but attentive and psychomotor performance remained unaffected.

Diazepam Tolerance Effects on Vestibular Function Testing, Part I: Saccadic Parameters during Electronystagmography

Objectives:

Benzodiazepines, particularly diazepam (DZ), are used in clinical practice to suppress acute vestibular symptoms. There have been limited studies looking at the effects of tolerance to DZ on parameters designed to measure the integrity of the vestibular system and its interaction with the oculomotor and balance systems.

Methods:

In a double-blinded, repeated-measures design, we randomized 30 young healthy men into one of two treatment groups (diazepam and placebo) and assessed with electro-oculography the effects of clinical divided doses of DZ on saccadic eye movements and sedation over 16 days.

Results:

Only sedation and saccadic latency were significant (p < .05) for treatment group, indicating selective effects on different central nervous system mechanisms. No significant effect for time was seen in any of the variables measured. Bonferroni t-test comparisons of the DZ group among 3 days were significant (p < .017) between baseline and day 3 for saccadic latency and accuracy and between day 3 and day 16 for self-ratings of sedation.

Conclusions:

Saccadic latency and accuracy and sedation ratings appear to be more sensitive to changes over time and less affected by subject variability than saccadic eye velocity. It remains questionable whether patients who have been on DZ for acute or extended periods of time need to discontinue the drug 48 hours before testing.

Neurocognitive costs and benefits of psychotropic medications in older adults

Psychotropic medications are widely used in older adults and may cause neurocognitive deficits. Older adults are at increased risk of developing adverse effects because of age-related pharmacodynamic and pharmacokinetic changes. This article provides a comprehensive review of the undesirable, and at times beneficial, effects of psychotropic medications. The review covers a wide range of medications that impair executive function, memory, and attention, as well as a much smaller group of medications that lead to improved neurocognitive function. Some of the most commonly used psychotropic medications in older adults, namely, antidepressants, sedatives, and hypnotics, are among the drugs that most consistently lead to cognitive impairments. Medications with anticholinergic properties almost invariably lead to neurocognitive dysfunction, despite symptom improvement. The neurocognitive costs and benefits of psychiatric medications should be considered in the context of disease treatment in older adults.

Cognitive effects of long-term benzodiazepine use: a meta-analysis

INTRODUCTION

While benzodiazepines are the most widely used psychotropic drugs, there are relatively few studies that have examined deficits in cognitive functioning after long-term use. The literature that is available is difficult to interpret due to conflicting results as well as a variety of methodological flaws.

OBJECTIVE

To systematically evaluate and integrate the available research findings to determine the effect of long-term benzodiazepine use on cognitive functioning using meta-analytical techniques.

METHODS

Thirteen research studies that employed neuropsychological tests to evaluate cognitive performance after long-term use of benzodiazepine medication met inclusion criteria. The neuropsychological tests employed in these 13 studies were each categorised as measuring one of 12 cognitive domains. Separate effect sizes were calculated for each of the 12 cognitive categories. Each study was only allowed to contribute one effect size to each cognitive category by averaging together the effect sizes from the same study if more than one type of test was used to measure a particular category. This strategy resulted in equal weight being given to each study per category, regardless of the number of tests in that category.

RESULTS

The overall mean number of patients who were benzodiazepine users was 33.5 (SD +/- 28.9) and the mean number of controls was 27.9 (SD +/- 19.6). The duration of benzodiazepine use ranged from 1 to 34 (mean 9.9) years. Long-term benzodiazepine users were consistently more impaired than controls across all cognitive categories examined, with effect sizes ranging in magnitude from -1.30 to -0.42. The mean weighted effect size was -0.74 (SD +/- 0.25). None of the effect sizes had 95% CIs that spanned zero and, therefore, all of these effects were significant and different to zero.

CONCLUSION

Moderate-to-large weighted effect sizes were found for all cognitive domains suggesting that long-term benzodiazepine users were significantly impaired, compared with controls, in all of the areas that were assessed. However, this study has several limitations, one being that it includes a relatively small number of studies. Further studies need to be conducted; ideally, well designed, controlled studies that thoroughly investigate certain areas of cognitive functioning and present data in such a way so as to be amenable to inclusion in a meta-analysis. Incorporating the information from these studies into a larger meta-analysis would allow for a more thorough and statistically sound investigation of the effects of moderator variables. The observation that long-term benzodiazepine use leads to a generalised effect on cognition has numerous implications for the informed and responsible prescription of these drugs.

Clinical pharmacology, clinical efficacy, and behavioral toxicity of alprazolam: a review of the literature

Alprazolam is a benzodiazepine derivative that is currently used in the treatment of generalized anxiety, panic attacks with or without agoraphobia, and depression. Alprazolam has a fast onset of symptom relief (within the first week); it is unlikely to produce dependency or abuse. No tolerance to its therapeutic effect has been reported. At discontinuation of alprazolam treatment, withdrawal and rebound symptoms are common. Hence, alprazolam discontinuation must be tapered. An exhaustive review of the literature showed that alprazolam is significantly superior to placebo, and is at least equally effective in the relief of symptoms as tricyclic antidepressants (TCAs), such as imipramine. However, although alprazolam and imipramine are significantly more effective than placebo in the treatment of panic attacks, Selective Serotonin Reuptake Inhibitors (SSRIs) appear to be superior to either of the two drugs. Therefore, alprazolam is recommended as a second line treatment option, when SSRIs are not effective or well tolerated. In addition to its therapeutic effects, alprazolam produces adverse effects, such as drowsiness and sedation. Since alprazolam is widely used, many clinical studies investigated its cognitive and psychomotor effects. It is evident from these studies that alprazolam may impair performance in a variety of skills in healthy volunteers as well as in patients. Since the majority of alprazolam users are outpatients, this behavioral impairment limits the safe use of alprazolam in patients routinely engaged in potentially dangerous daily activities, such as driving a car.

Preference for diazepam, but not buspirone, in moderate drinkers

The purpose of the present study was to determine the preference for buspirone, an anxiolytic predicted to have minimal abuse potential, in comparison with diazepam in moderate drinkers. Preference for diazepam and buspirone was assessed in 55 moderate drinkers using a seven-session procedure consisting of four sampling sessions followed by three choice sessions. On each sampling session subjects ingested five capsules, one every 30 min. Color-coded capsules contained placebo on two sessions and drug on two sessions. Each drug capsule contained diazepam (4 mg) for 30 subjects and buspirone (5 mg) for 25 subjects. On choice sessions subjects chose whichever of the two color-coded capsules, i.e., drug or placebo, they wished to take. After ingesting one capsule, every 30 min they had the option of ingesting another capsule of the same color and content, for a maximum of seven capsules over the session (maximum of 28 mg diazepam or 35 mg buspirone). In the diazepam group 70% of subjects chose diazepam over placebo on at least two of the three choice sessions, whereas in the buspirone group only 24% of subjects chose buspirone over placebo on at least two sessions. Both diazepam and buspirone increased measures of sedation. Only diazepam increased ratings of liking and impaired performance, whereas only buspirone decreased ratings of feeling Friendly. These results replicate previous findings indicating that diazepam has reinforcing effects in moderate drinkers. Further, these results demonstrate the pharmacological specificity of this effect by showing that buspirone did not function as a reinforcer under these same conditions.

Abuse liability of alprazolam relative to other commonly used benzodiazepines: a review

Nonhuman and human studies comparing the abuse liability of alprazolam to other commonly used benzodiazepines are reviewed. These studies are reviewed to determine to what extent prospective, controlled, experimental studies support opinions that alprazolam's abuse liability is greater than that of other commonly used benzodiazepines. Studies comparing the self-administration of alprazolam, the discriminative stimulus effects of alprazolam, self-reported effects of alprazolam, physiological dependence on alprazolam, and adverse effects of alprazolam relative to other benzodiazepines are reviewed. Overall, the experimental literature does not support the widely held belief that alprazolam's abuse liability is greater than that of other benzodiazepines, but much more research is needed. Such research should focus explicitly on alprazolam's reinforcing effects, and the nature and severity of the discontinuation syndrome associated with its long-term use. Important issues such as selection of an appropriate comparison drug, selection of an appropriate population, dosing regimen and test doses need to be considered in future studies.

The effects of repeated doses of clomipramine and alprazolam on physiological, psychomotor and cognitive functions in normal subjects

The effects of a 10 day administration of clomipramine (25-50 mg t.i.d.), alprazolam (0.25-0.75 mg t.i.d.) and placebo were assessed in normal volunteers in a double-blind cross-over study. A battery of physiological, psychomotor and cognitive tests was administered both before and 3 h after drug on days 1, 5 and 10. The effects of alprazolam on EEG and evoked potentials were characteristic of benzodiazepines; clomipramine had little effect. In contrast, reaction speed was markedly slowed by clomipramine but little affected by alprazolam. Neither drug produced any accumulation of effect on a verbal recall task but neither did tolerance develop to the acute impairments produced by active treatments. Alprazolam produced an increase in levels of forgetting, especially on day 5. Subjective ratings for mood and bodily symptoms were adversely affected by clomipramine but little altered by alprazolam. It is suggested that some of the differences between drug treatments may be due to differences in the speed of onset of tolerance.

Effects of single doses of alprazolam and diazepam, alone and in combination with ethanol, on psychomotor and cognitive performance and on autonomic nervous system reactivity in healthy volunteers

Effects of alprazolam, alone and in combination with ethanol, on psychomotor and cognitive performance were studied in healthy male volunteers and compared to effects of diazepam. Alprazolam 2 mg produced relatively long-lasting impairments on tests of tracking, verbal and nonverbal information processing, and memory, and decreased blood pressure without a change in heart rate or plasma norepinephrine levels. Although ethanol consumption was demonstrated to produce additive decrements in performance on certain tasks, there was little evidence to support a synergistic effect. Alprazolam 2 mg was accompanied by increased self-reports of side effects, especially drowsiness. Low dose alprazolam, diazepam, and ethanol produced significantly fewer side effects than 2 mg alprazolam, but significantly more than placebo.

A methodological comparison of two formulations of temazepam in pharmacokinetic and pharmacodynamic aspects

In a double-blind and cross-over study 12 healthy subjects took temazepam 20 mg in two different formulations (soft gelatine capsule or uncoated tablet) and matched placebo at one-week intervals. Plasma temazepam concentrations at 0.5, 1, 2, 3, 8, 12 and 24 hours after treatment were analyzed by gas chromatography. Psychomotor performance was measured objectively (digit symbol substitution, letter cancellation, Maddox wing test) and subjectively (visual analogue scales) before the drug intake and 1, 2 and 3 hours later and the plasma benzodiazepine concentrations were analyzed also by radioreceptor bioassay. The two different formulations were compared in pharmacokinetic and pharmacodynamic terms, and the gas chromatographic and radioreceptor assays were compared. The soft gelatine capsule produced higher peak plasma concentrations than the uncoated tablet. The computed AUCs and elimination half-lives proved to be similar after either formulation. A satisfactory correlation between the bioassayed benzodiazepine concentrations and chemically assayed temazepam was shown. In pharmacodynamic terms the results suggest a shorter and somewhat smaller subjective response for the capsule than for the tablet form.

Cognitive impairment in long-term benzodiazepine users

In view of the very extensive and often prolonged use of benzodiazepines in therapeutic practice, this study was designed to investigate whether or not cognitive ability is impaired in long-term benzodiazepine users, and to determine the nature and extent of any deficit. Fifty patients currently taking benzodiazepines for at least one year, thirty-four who had stopped taking benzodiazepines, and a matched control group of subjects who had never taken benzodiazepines or who had taken benzodiazepines in the past for less than one year were administered a battery of neuropsychological tests designed to measure a wide range of cognitive functions. It was found that patients taking high doses of benzodiazepines for long periods of time perform poorly on tasks involving visual-spatial ability and sustained attention. This is consistent with deficits in posterior cortical cognitive function.

The natural history of tolerance to the benzodiazepines

Dependence on benzodiazepines following continued use is by now a well-documented clinical phenomenon. Benzodiazepines differ in their dependence potential. The present studies were aimed at examining the possibility that differential rates of tolerance development might account for differences in dependence risk. Four studies are reported. The first three studies concerned normal subjects. The development of tolerance over a fifteen day period was demonstrated for three different benzodiazepines (ketazolam, lorazepam and triazolam) using two paradigms. Tolerance in terms of a reduction in effectiveness of a repeated given dose was most notable for the benzodiazepine with a medium elimination half-life (lorazepam) for physiological, behavioural and subjective measures. In the case of the drug with the longest elimination half-life (ketazolam) reduction in effectiveness could only be assumed to be occurring if account was taken of the steady increase in plasma concentrations of active metabolites. For this drug it seemed that the physiological measures were those most likely to demonstrate the development of tolerance. Although triazolam showed few significant drug effects on this paradigm (testing being 12 hours after ingestion of this short half-life benzodiazepine), tolerance was seen to develop on some subjective measures. Using an alternative method of testing tolerance, assessing responses to a diazepam challenge dose, a high degree of tolerance on two-thirds of the measures was observed in subjects when pretreated with the benzodiazepine with the most marked accumulation of active metabolites (ketazolam). The other two drugs also led to tolerance development on a range of measures; this was more marked for lorazepam than triazolam. Blunting of the growth hormone response to diazepam was the most sensitive and reliable method of detecting tolerance to the benzodiazepines. Symptoms on discontinuation of the two weeks' intake of the benzodiazepines were marked for all the drugs but unrelated to either the tolerance induced or the elimination half-life of the particular drug. A further clinical study revealed that tolerance persisted in a group of long-term benzodiazepine users for between four months and two years following complete abstinence from the drug. These patients appeared to be less affected by diazepam in terms of its commonly observed subjective effects, regardless of their original medication. These ex-long-term users of benzodiazepines were, however, more likely to manifest two specific types of effects--immediate 'symptom' reduction and exacerbation of 'withdrawal symptoms' over the subsequent week.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute and subchronic effects of Org 2305 and diazepam on psychomotor performance in man

Three doses (15, 30 and 60 mg) of Org 2305 (O 15, O 30 and O 60 respectively), a novel anxiolytic drug chemically related to mianserin, were compared with placebo and 15 mg diazepam (DZ) on human psychomotor performance in a double-blind, cross-over study with 15 healthy volunteers. Objective measurements (choice reaction, tracking, flicker fusion, Maddox wing, digit symbol substitution, memory recall) and subjective assessments (visual analogue scales) were done at baseline and 2 and 13 h after the first dose. This testing procedure was repeated on day 7 when administering the seventh consecutive daily night-time dose. After the first dose O 15 did not differ from placebo and O 30 rarely differed from placebo. O 60 impaired various objective functions similarly to, or less than DZ. Subjectively, DZ and O 60 were felt as sedative. During subchronic treatment, DZ caused some impairment of baseline due to accumulation of bioassayable benzodiazepines, but significant responses to the last DZ dose were less than those to the first dose. DZ but not O 60 was reported to have caused lethargy and clumsiness during subchronic treatment. In the doses used Org 2305 impaired psychomotor performance less than diazepam did. A dose of 60 mg Org 2305 may offer some advantage over 15 mg diazepam, provided that their anxiolytic effects are about similar.

Benzodiazepines, but not antidepressants or neuroleptics, induce dose-dependent development of tolerance to lorazepam in psychiatric patients

Psychomotor effects of oral lorazepam 3 mg were studied in psychiatric patients stratified into four groups: 1) a group of six patients with no previous use of psychotrophic drugs (NoD), 2) a group of 12 patients treated with antidepressants and/or neuroleptics (PsyD), 3) a group of 10 patients treated with low doses of benzodiazepines (BZs) (lowBZ), and 4) a group of nine patients treated with high doses of BZs (high BZ). Similar objective psychomotor tests and subjective assessments were administered under single-blind conditions to all treatment groups at baseline, after intake of placebo, and after intake of 3 mg lorazepam. Both lorazepam (CGC) and total BZs (bioassay) in serum were assayed. The results demonstrate that treatment with BZs induce dose-dependent development of tolerance to psychomotor effects of lorazepam. Antidepressants and neuroleptics failed to induce cross-tolerance to lorazepam. The rise in serum lorazepam concentrations after lorazepam intake was similar (about 28 micrograms/l) in all treatment groups, suggesting a functional, not dispositional, tolerance. However, the initial learning effect in psychomotor performance was poorer among BZ users than among others.

Task-dependent development of cross-tolerance to psychomotor effects of lorazepam in man

Development of cross-tolerance between lorazepam and four other benzodiazepines (BZ) was studied in two trials by measuring objective psychomotor performance and by subjective assessments. In trial I, nitrazepam 10 mg (NZ), temazepam 20 mg (TZ) or placebo were administered to 14 healthy students for 10 consecutive nights. After each pretreatment, psychomotor impairment by the challenge dose of lorazepam 3 mg (LZ) was measured. In trial II, responses to LZ after pretreatment with diazepam 5 mg (DZ) (8 subjects) or alprazolam 0.25 mg (AZ) (10 subjects), both t.i.d., were compared to LZ responses measured after one-month wash-out period. In trial I no cross-tolerance between BZs was found in objective tests, and LZ induced exophoria was even increased. However, the subjects rated LZ to cause less drowsiness after pretreatment with NZ in a situation where the manifestation of cross-tolerance was facilitated by ingestion of caffeine. In trial II a clear but task-dependent development of tolerance to the challenge dose of LZ was documented. One-week pretreatment with DZ reduced subjects responses to LZ. The total serum BZ activity bioassayed by radioreceptor method after intake of LZ was significantly (P less than 0.05) higher after pretreatment with DZ than in the end of wash-out period. Thus a functional cross-tolerance was documented on complex tasks after the subjects have been continuously working under DZ burden.

Interaction of diazepam or lorazepam with alcohol. Psychomotor effects and bioassayed serum levels after single and repeated doses

Nine healthy volunteers in a double-blind, cross-over trial received diazepam (DZ) 10 mg, lorazepam (LZ) 2.5 mg, or placebo (P). Serum benzodiazepine (BZ) was bioassayed (radioreceptor method) and psychomotor tests were carried out on Day 1 (before and 1 h after the first dose) and on Day 4 (before and after the fifth dose). In each session alcohol 1 g/kg was administered 1.5 h after drug intake and the measurements were repeated twice. Serum BZ concentrations, expressed as DZ equivalents (microgram/l), ranged from 390 to 440 and from 990 to 1240 measured 2 h 45 min after the first doses of DZ and LZ, respectively. On Day 1 BZ alone impaired psychomotor skills. LZ affected performance more in objective tests, but DZ was subjectively rated as causing more drowsiness. After the intake of alcohol, all groups showed impairment in various tests. The rank order was LZ + alcohol greater than DZ + alcohol greater than P + alcohol. Residual BZ activity on Day 4, measured 18 h after the fourth dose, averaged 290 and 450 micrograms/l after DZ and LZ, respectively. At the same time slight residual exophoria was found after both BZs. Tolerance to BZs on Day 4 was unambiguous only when drug effects were related to the bioassayed serum levels. The combined action of BZs and alcohol was similar on Days 1 and 4. However, a tendency to an increased drug-alcohol interaction during advanced treatment with DZ was seen in the body sway test.(ABSTRACT TRUNCATED AT 250 WORDS)