Reversal of triazolam- and zolpidem-induced memory impairment by flumazenil

The effects of flumazenil, a benzodiazepine receptor antagonist, on triazolam- and zolpidem-induced memory impairment were investigated. Sixty subjects received oral triazolam 0.5 mg, zolpidem 20.0 mg, or placebo at 10 a.m. (n = 20 per drug). Ninety minutes later, half of the subjects (n = 10) in each oral drug group were administered flumazenil 1.0 mg, while the remaining half received placebo (normal saline), through indwelling venous catheters. Learning/memory tests (including Simulated Escape, Restricted Reminding, Paired-Associates, and Repeated Acquisition) were administered at that time, and at 1.5-h intervals over the next 6 h. Triazolam/placebo and zolpidem/placebo drug combinations impaired memory on all tests (all Ps < 0.05). However, the triazolam/flumazenil and zolpidem/flumazenil groups showed no evidence of impairment during any test session. These results demonstrate that flumazenil 1.0 mg rapidly and lastingly reverses memory impairment caused by agonists of the benzodiazepine receptor. Furthermore, nonsignificant trends suggested that performance of the placebo/flumazenil group was consistently better than that of the placebo/placebo group, denoting a possible role of endogenous benzodiazepine agonists in natural sleep/wake processes.

Safety and side-effects of alprazolam. Controlled study in agoraphobia with panic disorder

BACKGROUND

The widespread use of benzodiazepines has led to increasing recognition of their unwanted effects. The efficacy of alprazolam and placebo in panic disorder with agoraphobia, and the side-effect and adverse effect profiles of both drug groups were measured.

METHOD

In London and Toronto 154 patients who met DSM-III criteria for panic disorder with agoraphobia were randomised to alprazolam or placebo. Subjects in each drug group also received either exposure or relaxation. Treatment was from weeks 0 to 8 and was then tapered from weeks 8 to 16.

RESULTS

Mean alprazolam dose was 5 mg daily. Compared with placebo subjects, alprazolam patients developed more adverse reactions (21% v. 0%) of depression, enuresis, disinhibition and aggression; and more side-effects, particularly sedation, irritability, impaired memory, weight loss and ataxia. Side-effects tended to diminish during treatment but remained significant at week 8. Despite this, the drop-out rate was low.

CONCLUSIONS

Alprazolam caused side-effects and adverse effects during treatment but many patients were willing to accept these.

Comparison of the daytime sleep and performance effects of zolpidem versus triazolam

Fifty healthy male subjects were administered zolpidem (5, 10, or 20 mg), triazolam (0.5 mg) or placebo, then attempted to sleep in a non-sleep-conducive environment. Subjects were awakened at 90 min post-drug (near peak blood concentration for both drugs) and tested on several cognitive tasks, including Two Column Addition, Logical Reasoning, and a Simulated Escape Task. This was followed by a second, 3.5-h sleep period. Hypnotic efficacy of the 20 mg zolpidem (Z-20) dose was similar to that of the 0.5 mg triazolam (TRIAZ) dose, as indicated by comparably shortened sleep latencies and lengthened total sleep times. Though accuracy on most performance measures was not affected by either drug, a reduction in speed of responding on logical reasoning and addition tasks was evident for the TRIAZ group at 90 min post-drug (Ps less than 0.05). On the simulated escape task, only triazolam significantly increased the mean number of errors, and interfered with subsequent memory of the task. Thus, zolpidem had milder effects on performance than triazolam. However, 60% of the Z-20 subjects experienced mild, adverse physical reactions. Performance differences between somnogenically comparable doses of zolpidem and triazolam may be due to their differential affinities for the BZ1 and BZ2 receptor subtypes.

Next-day memory impairment with triazolam use

The prevalence, rate, and degree of memory impairment for next-day activities during a short, intermittent course of bedtime doses of triazolam, temazepam, and placebo were assessed in a double-blind parallel-group study. 5 of the 6 subjects in the triazolam group reported at least one episode of next-day memory impairment/amnesia, with a total of 12 episodes being reported for the 30 subject-drug nights (a rate of 40%). In the temazepam group there were no such episodes of memory impairment. Immediate and delayed recall were also tested and related to whether active drug or placebo had been taken the night before. Impairment of delayed recall was significantly and several times greater than that in the temazepam or placebo groups. Next-day memory impairment/amnesia after a bedtime dose of triazolam tended to increase with continued or intermittent drug use. Cognitive impairments associated with triazolam probably represent a spectrum of organic brain dysfunction, with memory impairment/amnesia and confusion being the commonest, and milder manifestations and hallucinations and delusions the more severe and less common, features.

Administration of triazolam prior to recovery sleep: effects on sleep architecture, subsequent alertness and performance

The effects of triazolam (0.125, 0.25, and 0.5 mg) versus placebo on recovery sleep staging, subsequent alertness and psychomotor performance were evaluated in humans. Forty-five healthy male subjects were deprived of sleep for 24 h, then administered a single dose of triazolam or placebo using a double-blind procedure. Subjects then attempted to obtain recovery sleep under non-sleep-conducive conditions (sitting upright in a well-lit, crowded chamber) for the next 6 h, followed by 18 more hours of sleep deprivation. During all sleep deprivation periods subjects were tested bihourly on a performance assessment battery which included symbol digit modalities tests (SDMT), four-letter search (FLS), logical reasoning (LR), time estimation (TE), visual vigilance (VV), and short term memory (STM) tasks. Sleepiness levels were measured objectively with multiple sleep latency tests (MSLT) and subjectively with the Stanford Sleepiness Scale (SSS). Compared to placebo, all doses of triazolam resulted in increased amounts of stage 3-4 sleep, and the 0.5 mg dose significantly reduced awakenings (Ps less than 0.05). Although subjects receiving triazolam averaged 21-42 min more total sleep time (TST) than subjects receiving placebo, differences in TST were not statistically significant. Apparent triazolam-mediated benefits to sleep quality resulted in no obvious improvements in performance or alertness levels during subsequent sleep deprivation. It was concluded that the increases in stage 3-4 sleep amounts were most likely due to triazolam-mediated increases arousal thresholds, and the triazolam mediated changes in sleep parameters obtained in the present study were not indicative of substantial changes in the recuperative value of sleep.