Differential effects of the 1,4 and 1,5 benzodiazepines on performance in healthy man

Clinical considerations in transitioning patients with epilepsy from clonazepam to clobazam: a case series

INTRODUCTION

In treating refractory epilepsy, many clinicians are interested in methods used to transition patients receiving clonazepam to clobazam to maintain or increase seizure control, improve tolerability of patients' overall drug therapy regimens, and to enhance quality of life for patients and their families. However, no published guidelines assist clinicians in successfully accomplishing this change safely.

CASE PRESENTATIONS

The following three case reports provide insight into the transition from clonazepam to clobazam. First, an 8-year-old Caucasian boy with cryptogenic Lennox-Gastaut syndrome beginning at 3.5 years of age, who was experiencing multiple daily generalized tonic-clonic, absence, myoclonic, and tonic seizures at presentation. Second, a 25-year-old, left-handed, White Hispanic man with moderate mental retardation and medically refractory seizures that he began experiencing at 1 year of age, secondary to tuberous sclerosis. When first presented to an epilepsy center, he had been receiving levetiracetam, valproate, and clonazepam, but reported having ongoing and frequent seizures. Third, a 69-year-old Korean woman who had been healthy until she had a stroke in 2009 with subsequent right hemiparesis; as a result, she became less physically and socially active, and had her first convulsive seizure approximately 4 months after the stroke.

CONCLUSIONS

From these cases, we observe that a rough estimate of final clobazam dosage for each mg of clonazepam under substitution is likely to be at least 10-fold, probably closer to 15-fold for many patients, and as high as 20-fold for a few. Consideration and discussion of the pharmacokinetic, pharmacologic, and clinical properties of 1,4- and 1,5-benzodiazepine action provide a rationale on why and how these transitions were successful.

Cytogenetic activity of newly synthesized 1,5-benzodiazepines in normal human lymphocyte cultures

INTRODUCTION

Many different types of benzodiazepine medications exist to treat a wide array of psychological and physical diseases based on dosage and implications. Benzodiazepines are generally considered as safe and effective drugs in short term; however, cognitive impairments and paradoxical effects occasionally occur. Our recent studies have shown that some 1,4-benzodiazepines exhibit cytogenetic activity (alprazolam, diazepam, and lorazepam) in normal human lymphocyte cultures. 1,5-Benzodiazepine derivatives are used in the synthesis of fused ring compounds, to study the chemical structure-pharmacological activity correlation. We synthesized four compounds of this category with small structural differences.

AIM

The aim of this study was to investigate their cytogenetic activity in vitro at doses equivalent to the per os doses of the used 1,4-benzodiazepines. Sister chromatid exchanges (SCEs), proliferation rate index, and mitotic index were evaluated in lymphocytes of peripheral blood cultures from two healthy donors.

RESULTS

Three of the newly synthesized compounds exhibited positive cytogenetic activity (statistically significant reduction of SCEs, p < 0.01, t-test), without showing cytostatic properties.

CONCLUSION

The observed reduction of the lymphocytes' SCEs because of 1,5-benzodiazepines' activity is remarkable and requires further investigation to improve pharmacological effects.

Drug-Facilitated Robbery or Sexual Assault

Amnesia following sedative-hypnotic drug exposure is discussed. Anterograde amnesia clearly occurs with many benzodiazepines. Several drugs are assessed: benzodiazepines and two hypnotics in particular that are structurally unrelated to the benzodiazepines but share some of their properties: zolpidem and zopiclone. The amnesic effects of these drugs are described, memory process, biology of memory, and memory process impairment documented. With these drugs anterograde amnesia has been demonstrated to be dose dependent. This effect is associated with hypnotic drugs, however, the receptors are different. As regards forensic medicine, a significant and specific type of amnesia should be considered: amnesia automatism or amnesic complex automatism. Also, several cases observed in our laboratory are presented to demonstrate the impact of amnesia.

The effects of temazepam and ethanol on human psychomotor performance

We have studied the effects of temazepam, alone and in combination with ethanol, on psychomotor performance in six healthy men and women using a battery of five microcomputer-based tasks before and 30, 90, and 150 min after treatment. The tests were pursuit tracking, divided attention, two four-choice reaction time tests and tapping rate. The entire battery required 25 min. The subjects also reported their mood at each testing time using a computerized bipolar mood scales test. Temazepam (15 mg) plus ethanol (peak blood concentration of 11 mmol.l-1) significantly impaired divided attention, tracking, and reaction time over a 3 h period. There was significant impairment versus placebo for each drug alone on some of the tests. Plasma and urine concentrations of temazepam and temazepam glucuronide were measured, but there was no significant temporal correlation between impairment and drug or metabolite concentration in either plasma or urine. The subjects knew when they had taken ethanol, but could not discriminate temazepam from ethanol whether alone or in combination. The subjects rated their performance similarly after each of the four treatment conditions. The performance on the tracking, divided attention, and PAB reaction time tasks used in this study was impaired by a combination of temazepam and ethanol in doses which may not cause impairment when each is given alone.

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.

CGP 11.952: an experimental benzodiazepine derivative. Effects on cognitive functioning in patients with epilepsy

1. In two open studies using patients with intractable epilepsy, the effects of CGP 11.952, a triazolyl benzophenone, on cognitive functioning were assessed by means of a computerized neuropsychological battery. 2. In the first study CGP 11.952 turned out to have a positive effect on information processing speed, perceptual sensitivity and preciseness of responses. 3. Negative effects were found on reaction time. 4. In the second study this latter effect was less clear. 5. A striking result was the less negative effect on memory consolidation under influence of CGP 11.952 in comparison with other benzodiazepines.

Clobazam: pharmacological and therapeutic profile

1 Clobazam is a 1,5-benzodiazepine the pharmacological profile of which differs from that of the 1,4 benzodiazepines in that it displays a wide separation of psychosedative or 'tranquillizing' properties from impairment of motor coordination. This is associated with a relative lack of muscle relaxant activity. 2 In man it seems to be an effective anxiolytic agent when given in daily doses of 20-30 mg but produces minimal effects on psychomotor performance at these dose levels. 3 Clobazam has a long elimination half-life of about 18 h; the main metabolite is N-desmethylclobazam. Clobazam seems to share the good safety and tolerability characteristics of the 1,4 benzodiazepines.