The effects of zolpidem and zopiclone on daytime sleepiness and psychomotor performance

Zolpidem (ZLP), which has selective affinity to the BZ1 (omega 1) receptor and a short half-life, is a novel hypnotic. The objective of this study is to compare the residual effects of standard clinical doses of ZLP and zopiclone (ZPC), a short-acting hypnotic marginally selective for the BZ1 (omega 1) receptor, given in a single dose on daytime sleepiness and psychomotor function. This study was carried out as a double-blind cross-over study with 10 mg ZLP, 7.5 mg ZPC and a placebo in 12 healthy male adults. In the multiple sleep latency test, sleep latency was not reduced but increased by ZLP and ZPC as well as the placebo when drug plasma levels had nearly reached the peak. Subjects administered ZLP were significantly more feeble, lethargic and antagonistic in mood rating scales than those administered ZPC. The incidence of severe behavioral side effects was higher in the case of ZLP than in the case of ZPC over the same period. Sleep latency the next morning was significantly shorter in the case of ZPC than in the case of ZLP or the placebo. The tapping test performed at the same time demonstrated that the number of taps was significantly less in the case of ZPC than in the case of ZLP or the placebo. The results of the present study suggest that ZLP acts more rapidly than ZPC. On the other hand, ZLP has less residual effect on sleepiness and psychomotor function the next morning.

The effect of zolpidem and zopiclone on memory

The effect of 10 mg of zolpidem (ZLP) on memory function was evaluated in healthy male adults using word recall test, passage recall test, and Sternberg's memory scanning task. This study was carried out as a double-blind cross-over study with 7.5 mg of zopiclone (ZPC) and a placebo. No difference was noted between the active drugs and placebo in the number of words recalled from the word list presented before administration. No evidence of retrograde amnesia was suggested. However, encoding ability was slightly affected as indicated by a decrease in the number of words recalled from the list presented after administration. Slight impairment of a delayed recall was noted for both of the active drugs, but the effect disappeared the next morning. In the memory scanning task, ZLP prolonged a non-specific component of reaction time 1.5 h after administration, but the effect disappeared after 12.5 h. ZPC did not prolong the reaction time. The two active drugs showed no specific effects on either memory scanning or response-selection stage in short-term memory at any time. The findings suggest that residual effects did not reach clinical significance at the standard dosage, although the active drugs slightly affected encoding ability and retention soon after administration.

Comparison of pharmacokinetics of NS-105, a novel agent for cerebrovascular disease, in elderly and young subjects

Pharmacokinetics of NS-105, a novel agent for cerebrovascular disease, in elderly subjects were compared with those in younger subjects. Fourteen healthy male volunteers (7 elderly subjects aged 68-79 years and 7 young subjects aged 20-32 years) were included in the study. In a parallel group design, a tablet containing 100 mg NS-105 was administered orally after breakfast. One young subject was excluded from the pharmacokinetic analyses owing to an insufficient urine collection. The maximum plasma concentration (Cmax) was higher in the elderly (3.06 +/- 0.69 vs. 2.13 +/- 0.34 micrograms/ml, the elderly vs. the young, mean +/- SD, p = 0.0117) and area under the plasma concentration curve (AUC) was also higher in the elderly (24.6 +/- 4.4 vs. 14.4 +/- 3.1 micrograms.hr/ml, p = 0.0006). There is a tendency that time to reach Cmax was longer in the elderly (2.1 +/- 1.1 vs. 1.3 +/- 0.5 hr, p = 0.1199), and a tendency of prolongation of elimination half-life. Urinary recovery of NS-105 was less in the elderly up to 8 h after administration, while total recovery of the dose was not different in the two groups. Total clearance was reduced in the elderly (0.076 +/- 0.013 vs. 0.121 +/- 0.025l/kg/hr, p = 0.0013) and the decrease seemed to be mainly due to a decrement in renal clearance of the drug in the elderly. A significant correlation was found between renal clearance of NS-105 and creatinine clearance of each subject (r = 0.583, p = 0.0364). These observations indicate that the plasma concentration of NS-105 will increase in elderly subjects mainly due to a decrement in renal clearance of the drug. Careful observation is needed when prescribing the drug to an elderly patient.

Epidemiological study on sleep habits and insomnia of new outpatients visiting general hospitals in Japan

A large scale epidemiological survey of sleep habits, specifically for insomnia, was conducted using 6277 new outpatients from 11 general hospitals in Japan. They were requested to answer a questionnaire newly designed for this study, which consisted of 34 questions concerning sociodemographic characteristics, current medical conditions, sleep habits, current or past sleep complaints, symptoms of parasomnia, use of hypnotics/anxiolytics and other aspects of daily life. Insomnia was the focus of analysis using chi2 statistics and, additionally, logistic regression to explore the predictors of insomnia. Bedtime was 23:30 and wake-up time was 6:35 on average, with a mean sleep time of 6.77 h on weekdays. The number of subjects with current sleep complaints was 1276, of which 735 (11.7% of the total sample) had insomnia lasting for 1 month or more. Only 37.6% of those were taking hypnotics and/or anxiolytics. Old age, female sex, neurology, psychiatry, early bedtime, late wake-up time, living alone and dissatisfaction with the bedroom environment for sleep were found to be associated with long-term insomnia. This study helps to provide a framework for further studies using the general population.

Pharmacokinetic and pharmacodynamic interactions among haloperidol, carteolol hydrochloride and biperiden hydrochloride

A beta-adrenoceptor blocker and an anticholinergic agent are often prescribed concomitantly for the treatment of neuroleptic-induced akathisia. The aim of this study was to investigate possible pharmacokinetic interactions of neuroleptic haloperidol with the beta-blocker carteolol and the anticholinergic biperiden. In a 5-step, open-labeled, oral single-dose study, eight healthy male volunteers received 2 mg haloperidol, 10 mg carteolol hydrochloride, and 2 mg biperiden hydrochloride: first each drug alone, then a combination of haloperidol and carteolol, and then all three drugs concurrently. Serum concentrations of haloperidol, carteolol, and biperiden were determined up to 24 hr postdosing, and a safety evaluation was conducted throughout the study. Carteolol increased the area under the haloperidol serum concentration-time curve (AUC0-t) 1.4-fold (P = 0.0014) and decreased the serum clearance of haloperidol up to 67% (P = 0.0127). Biperiden reduced the serum haloperidol concentrations increased by the administration of carteolol. No significant changes of the serum pharmacokinetics of carteolol and biperiden were found as a result of any drug combinations. Adverse events of the central nervous system such as sleepiness and changes in pupil size were observed, but all were mild with clinical insignificance.