飞行员服用扎来普隆诱导午睡的效果及对地面抗荷能力的影响观察

目的 观察飞行员服用短效催眠药扎来普隆诱导午睡的效果及对其地面抗荷能力的影响.方法 40名健康疗养期间的飞行员为试验对象,分为扎来普隆组和安慰剂组(n=20).于午餐后1 h分别单剂量口服药物或安慰剂15 mg,睡眠2～2.5 h,用药3 h后进行主观睡眠质量和嗜睡感自评,以及地面抗荷能力测评.后者的评价指标包括L-1抗荷动作小腿、大腿和腹部肌力,心率(HR),肱动脉收缩压(SBP)和G(+Gs)值.进行服药前后对比分析以及扎来普隆组与安慰剂组同对比分析.结果 扎来普隆组服药后的主观睡眠质量(5.30±0.69分)较服药前(4.75±0.88分)明显提高(t=2.02,P<0.05);觉醒后两组间的主观嗜睡感无明显差异.扎来普隆组服药前后及扎来普隆与安慰剂两组问的地面抗荷能力均无显著性差异(P>0.05).所有受试对象用药后均无明显不良反应.结论 单剂量服用15 mg扎来普隆可改善飞行员的午睡质量,用药3h后对飞行员的地面抗荷能力无明显影响.     

两种剂量水平的扎来普隆对正常人认知操作能力和前庭功能的影响

目的 比较两种剂量水平的扎来普隆对正常人认知操作能力和前庭功能的影响.方法 8名健康青年男性志愿者在3次试验(每次间隔1周)中交叉服用扎来普隆10 mg、15 mg和安慰剂,采用随机双盲设计给药,分别在服药前4 h、服药后1、2、3、4、6、8 h各完成一次认知能力测试,内容包括单双重任务(即计算机控制的四数连加、心理运动及二者复合的双重任务)能力;光刺激反应时及运动时;临界闪光融合频率(CFF).另6人参加前庭功能测评,试验设计与上述相同,测试内容包括视动眼震(OKN)、前庭眼动反射(VOR)、视前庭眼动反射(VVOR)和前庭眼动反射固视抑制(VOR-Fix).用重复测量的方差分析比较不同药物组和用药后不同时间观察指标的差别. 结果 与安慰剂组相比,两种剂量扎来普隆组的认知操作指标无明显变化,但OKN、VOR增益明显降低(F值分别为10.81、39.64,P＜0.05),用药后2～3 h恢复正常,其余前庭功能指标各组无明显差异.结论 服用扎来普隆10 mg和15 mg对认知操作能力无明显副作用,对前庭功能的轻度不良影响在用药3 h后恢复正常.     

扎来普隆胶囊与艾司唑仑片对比治疗失眠症的临床疗效观察

目的观察新型镇静催眠药扎来普隆治疗失眠症的疗效。方法58例失眠症患者随机接受扎来普隆胶囊5-10mg和艾司唑仑1-2mg治疗，其中扎来普隆组30例，艾司唑仑组28例。两组患者均治疗7天，停药后随访7天。结果治疗7天后，扎来普隆组总有效率76．67％，艾司唑仑组总有效率71.43％，P〉0．05，说明扎来普隆和艾司唑仑对失眠均有效。扎来普隆组早段失眠程度和频度评分差值均显著大于艾司唑仑组（P〈0．05），显示扎来普隆对早段失眠的改善优于艾司唑仑。两组常见不良反应为口干、食欲下降、头晕及嗜睡，发生率无统计学差异。停药后反弹性失眠发生率艾司唑仑组（14．29％）高于扎来普隆（3．33％），但亦无统计学差异。结论扎来普隆与艾司唑仑均有改善睡眠的作用。扎来普隆对早段失眠的改善更为明显，且停药后反跳率较低，治疗睡眠障碍安全有效。     

服用三唑仑对汽车兵夜间睡眠质量和次日汽车驾驶能力的影响

目的 观察服用三唑仑对汽车兵夜间睡眠质量和次日汽车驾驶能力的影响,为今后在飞行人员中应用提供试验依据.方法 60名男性汽车兵随机分为安慰剂组和三唑仑组（各组n=30）.试验第1日8：30和14：30各完成1次考核场汽车驾驶任务,在夜间0：00两组分别服用药物（三唑仑0.25 mg或安慰剂）后睡眠5.5 h,于次日7：00、10：00、13：00和16：00（用药后7～16 h）完成4次相同的驾驶任务,测定指标包括：主观睡眠质量、斯坦福嗜睡量表和自认疲劳分级量表评分,考核场汽车驾驶成绩,视听反应能力和临界闪光融合频率.结果 与安慰剂组相比,三唑仑组的主观睡眠质量明显提高,而汽车驾驶成绩、视听反应能力和闪光融合频率两组无明显差异.结论 常规单剂量服用三唑仑具有提高汽车兵睡眠质量的效果,用药7 h后对汽车驾驶能力无明显不良影响.     

莫达非尼对睡眠剥夺汽车兵汽车驾驶能力和疲劳感的影响

目的 观察36 h睡眠剥夺（SD）条件下服用莫达非尼对汽车兵汽车驾驶能力和疲劳感的影响.方法 60名男性汽车兵随机分为安慰剂组和莫达非尼组（各组n=30）.试验第1日起床（6：00）后,36 h保持不睡眠,于当日夜间23：00、第2日5：00、11：00三次服用莫达非尼或安慰剂200 mg.于试验第1日8：30和14：30及用药后4个时刻（即试验第2日7：00、10：00、13：00、16：00）共完成6次驾驶任务.测定指标包括考核场汽车驾驶能力、视听反应能力和临界闪光融合频率（CFF）、斯坦福嗜睡量表和自认疲劳分级量表评分.结果 两组的汽车驾驶成绩和视听反应能力无明显差异.与安慰剂组相比,莫达非尼组的CFF明显增加、主观嗜睡和疲劳感显著降低. 结论 36 h SD条件下分次服用常规剂量的莫达非尼具有显著降低机体疲劳感的作用,且对汽车驾驶能力无明显不良影响.     

催眠药扎来普隆、三唑仑、唑吡坦和佐匹克隆对认知操作能力影响的比较

目的 比较催眠药扎来普隆、三唑仑、唑吡坦和佐匹克隆对正常人认知操作能力的影响.方法 8名健康青年男性志愿者,在5次试验（每次间隔1周）中交叉服用扎来普隆10 mg、三唑仑0.25 mg、唑吡坦10 mg、佐匹克隆7.5 mg和安慰剂,采用随机双盲设计给药,分别在服药前4 h、服药后1、2、3、4、6、8、10 h各完成1次认知能力测试,同时观察药物不良反应.测试内容包括：①单双重任务能力（包括计算机控制的4数连加、心理运动能力及二者复合的双重任务）;②光刺激反应时及运动时;③临界闪光融合频率.用重复测量的方差分析比较不同药物和用药后不同时间认知能力的差别.结果 与安慰剂相比,扎来普隆对各项指标无明显不良影响;三唑仑使心理运动能力和临界闪光融合频率下降;唑吡坦和佐匹克隆明显降低心理运动能力、双重任务保持率和临界闪光融合频率.此外,佐匹克隆还显著降低双重任务正确率.用药后约6 h各组的认知能力恢复正常.结论 基于认知操作能力的影响评价,扎来普隆是4种短效催眠药中最安全的药物.     

莫达非尼对军事飞行学员飞行工作能力和情感状态的影响

目的 观察莫达非尼对军事飞行学员飞行工作能力和情感状态的影响. 方法 21名男性飞行学员分两组：安慰剂组（n=10）和莫达非尼组（n=11）.在飞行前2 h（10：30）分别服用莫达非尼或安慰剂200 mg.对飞行活动中的心电进行连续监测,完成飞行任务后由飞行教员对飞行操作能力进行评价.此外,比较两组飞行前后的基本生命体征、视反应时、临界闪光融合频率和主观嗜睡感、疲劳感以及情绪情感状态的变化. 结果 与安慰剂相比,服用莫达非尼对飞行操作、生命体征、视反应时、临界闪光融合频率等指标均无明显影响,但使飞行中心率明显增加（平均增加15.7%,P＜0.01）、飞行后RPE量表的疲劳感积分明显降低（平均降低10%,P＜0.05）、POMS量表的“有力好动”感积分明显升高（平均升高20%,P＜0.05）. 结论 服用常规单剂量莫达非尼（200 mg）对飞行工作能力无明显不良影响,并有明显提高机体应激反应能力、降低主观疲劳感的作用.     

扎来普隆胶囊的人体药代动力学研究

目的　研究国产扎来普隆胶囊在中国人体内的药代动力学特征。方法　 2 0名健康志愿者单剂量口服 15mg扎来普隆胶囊 ,采用高效液相色谱法测定血浆中扎来普隆浓度。结果　扎来普隆胶囊药 -时曲线符合一房室模型 ,其Cmax　为 (6 1.6 0±16 .71)ng·ml-1;Tmax　为 (0 .99± 0 .2 2 )h ,Ke为 (0 .76± 0 .11)h ,T1/ 2 (ke)　　为 (0 .93± 0 .13)h-1;AUC0 -8为 (12 8.5 9± 2 9.0 2 )ng·ml-1·h-1;AUC0 -∞ 为 (130 .34± 2 9.2 7)ng·ml-1·h-1,与国外文献报道基本一致。结论　本研究可为扎来普隆胶囊的临床应用提供药代动力学参数     

NMDA、甘氨酸、阿片受体与硫喷妥钠催眠作用的关系

目的探讨硫喷妥钠催眠作用与N-甲基-D-天冬氨酸(NMDA)受体、阿片受体和甘氨酸受体的关系。方法120只昆明种小鼠,雌雄不拘,随机分成NMDA组、纳络酮组和士的宁组。实验小鼠均于腹腔注射50mg/kg硫喷妥钠,待翻正反射消失1min后,NMDA组40只小鼠鞘内分别注射人工脑脊液(aCSF)和25、50、75ngNMDA(n=10);纳络酮组40只小鼠腹腔分别注射生理盐水(NS)和1.0、2.0、4.0mg/kg纳络酮(n=10);士的宁组40只小鼠腹腔分别注射NS和0.5、1.0、2.0mg/kg士的宁(n=10),记录小鼠睡眠时间。结果NMDA对硫喷妥钠催眠小鼠的睡眠时间无明显影响(P>0.05);而纳络酮或士的宁均能明显延长其睡眠时间(P<0.01)。结论NMDA受体与硫喷妥钠的催眠作用无明显关系,而甘氨酸受体和阿片受体均介导了硫喷妥钠的催眠作用。     

消痰解郁方对急进西部高原军人睡眠质量的影响

目的 观察中药消痰解郁方对急进西部高原军人睡眠质量的影响.方法 采用匹兹堡睡眠质量指数量表(PSQI)对550名急进高原军人进行调查,筛选出睡眠障碍军人100例,按照前瞻、完全随机、安慰剂对照方法分为中药治疗组和安慰剂对照组(n=50),共治疗2周,治疗前后测评患者P SQI总分及各因子分,观察临床疗效及不良反应.结果 急进高原军人PSQI总分及各因子得分均显著高于正常成人,睡眠紊乱因子分显著高于失眠症患者,总分及其余各因子得分显著低于失眠症患者.消痰解郁方可降低睡眠障碍军人PSQI总分、主观睡眠质量、入睡时间、睡眠时间、睡眠效率等因子分值,差异有统计学意义(P＜0.05,P＜0.01),总有效率为91.49％,优于安慰剂对照组(P＜0.01),且无不良反应.结论 急进西部高原军人睡眠质量不佳,消痰解郁方可改善急进西部高原军人睡眠质量,安全有效.     

Usefulness of temazepam and zaleplon to induce afternoon sleep

Insufficient daytime sleep may result in reduction of effectiveness and safety during overnight military missions. The usefulness of temazepam and zaleplon to optimize afternoon sleep and their effects on performance and alertness during a subsequent night shift were studied. Method: In a randomized double-blind within-subjects design, 11 subjects took 20 mg of temazepam, 10 mg of zaleplon, or placebo before a 5:30-10:00 p.m. sleep period. Sleep length and quality were measured. Subjects were kept awake throughout the night while alertness, cognitive performance, and muscle power were repeatedly measured. Results: Temazepam provided significantly longer and qualitatively better sleep than zaleplon or placebo. During the night, sleepiness increased and muscle power was impaired in all conditions. Better sleep was correlated with less sleepiness during the night. Conclusion: Temazepam is useful to optimize a 4.5-hour afternoon sleep before overnight missions. Irrespective of hypnotic treatment, sleepiness and fatigue increased during the night shift.     

Impact of melatonin, zaleplon, zopiclone, and temazepam on psychomotor performance

INTRODUCTION: Modern military operations may require pharmaceutical methods to sustain alertness and facilitate sleep in order to maintain operational readiness. In operations with very limited sleep windows, hypnotics with very short half-lives (e.g., zaleplon, t(1/2) 1 h) are of interest, while with longer sleep opportunities, longer acting agents (e.g., zopiclone, temazepam (t(1/2) 4-6 hours) may be used. This study was designed to compare the effect of a single dose of zaleplon, zopiclone, temazepam, and melatonin on psychomotor performance and to quantify the post-ingestion time required for return to normal performance. METHOD: There were 23 subjects (9 men, 14 women), 21-53 yr of age, assessed for psychomotor performance on 2 test batteries (4 tasks) that included a sleepiness questionnaire. Psychomotor testing was conducted prior to, and for 7 h after, ingestion of a single dose of each of placebo, zaleplon 10 mg, zopiclone 7.5 mg, temazepam 15 mg, and time-released melatonin 6 mg. The experimental design was a double-blind cross-over with counter-balanced treatment order. RESULTS: Zaleplon, zopiclone, and temazepam impaired performance on all four tasks: serial reaction time (SRT), logical reasoning (LRT), serial subtraction (SST), and multitask (MT). Melatonin did not impair performance on any task. The time to recovery of normal performance for SRT during the zaleplon, zopiclone and temazepam conditions were 3.25, 6.25, and 5.25 h respectively; for LRT were 3.25, >6.25, and 4.25 h; for SST were 2.25, >6.25, and 4.25 h, and for MT were 2.25, 4.25, and 3.25 h. The recovery time to baseline subjective sleepiness levels for zaleplon, zopiclone, temazepam, and melatonin were 4.25, >6.25, 5.25, and >4.25 h, respectively. CONCLUSIONS: In spite of a prolonged period of perceived sleepiness, melatonin was superior to zaleplon in causing no impact on performance. The remaining drugs listed in increasing order of performance impact duration are zaleplon, temazepam, and zopiclone.     

Melatonin and zopiclone as pharmacologic aids to facilitate crew rest.

PURPOSE: In response to mission imperatives, transport aircrews must often sleep at inappropriate circadian times resulting in inadequate sleep. This study was undertaken to determine whether either melatonin or zopiclone could facilitate early circadian sleep, and to assess whether either of these medications would result in a psychomotor performance decrement which would preclude their use in aircrew. METHOD: Thirteen subjects from DCIEM completed a double-blind cross-over protocol. All subjects were assessed for psychomotor performance during 3 drug conditions (placebo, 10 mg melatonin, and 7.5 mg zopiclone), which were separated by one week. Each of these conditions involved 2 nights of sleep, back-to-back, with the first night being a normal circadian control sleep (23:00 h bedtime, arising at 06:45 h), and the second night being an early circadian drug sleep (drugs at 16:45 h, 17:00 h bedtime, arising at 23:45 h). All subjects were tested for psychomotor performance, on both nights of each of the 3 drug conditions, pre- and post-sleep. Further, during the early circadian drug night, all subjects were tested every hour after arising at 23:45 h (24:00 h until 07:00 h. At the beginning of each psychomotor test session, subjects were asked for their subjective levels of sleepiness and fatigue. RESULTS: Relative to placebo (339.5 min) the subjects slept more on melatonin (370.2 min, p < 0.01), and zopiclone (373.3 min, p < 0.01). Performance in serial reaction time (SRT) task (p < 0.001), logical reasoning task (LRT) (p < 0.001), serial subtraction task (SST) (p < 0.02), and Multitask (MT) (p < 0.03) were impaired for all 3 drug conditions immediately on awakening, compared with pre-sleep performance, as a result of a sleep-inertia effect. With respect to the subjective data, sleep inertia effects were evident for sleepiness (p < 0.001), mental fatigue (p < 0.002), and physical fatigue (p < 0.05). For SRT, LRT, and SST, performance recovered to pre-sleep levels within 1.25 h of awakening, and for MT recovery occurred 2.25 h after awakening. There were no differences in performance or subjective measures between placebo, melatonin and zopiclone. CONCLUSIONS: Both zopiclone and melatonin improved sleep relative to placebo. After sleep inertia, performance recovered to pre-sleep levels for all tasks and was sustained at that level throughout the balance of the testing period. There was no impact of melatonin or zopiclone on performance measures compared with placebo.     

降压药对人体认知操作能力和主观嗜睡感的影响

目的评价服用4种降压药贝那普利、阿替洛尔、氨氯地平和氯沙坦对正常人中枢神经系统功能的影响.方法 8名健康青年男性志愿者,在6次试验（每次间隔1周）中交叉服用贝那普利10 mg、阿替洛尔100 mg、氨氯地平10 mg、氯沙坦100 mg、唑吡坦10 mg和安慰剂,采用随机双盲设计给药,分别在服药前4 h,服药后1、2、3、4、6、8和10 h各完成一次计算机控制的单双重任务（包括四数连加、心理运动及两者复合的双重任务）能力测试;同时观察主观嗜睡度的变化.用重复测量的方差分析比较不同药物和用药后不同时间的差别.结果与安慰剂相比,唑吡坦对中枢能力产生明显不良影响：心理运动能力呈下降趋势、双重任务正确率明显降低（P＜0.05）、主观嗜睡度显著增加（P＜0.05）,用药后约6 h恢复正常;但4种降压药对人体认知操作能力和主观嗜睡感均无明显不良影响.结论单次服用贝那普利10 mg、阿替洛尔100 mg、氨氯地平10 mg或氯沙坦100 mg对人体认知操作能力和主观嗜睡感无明显不良影响.     

Performance following a sudden awakening from daytime nap induced by zaleplon

BACKGROUND: Zaleplon appears to be a prime candidate for assisting individuals in obtaining sleep in situations not conducive to rest (i.e., a short period during the day). However, should an early unexpected awakening and return to duty be required, the effect on performance is not known. HYPOTHESIS: Zaleplon (10 mg) would negatively affect human performance for some duration, compared with placebo, after a sudden awakening from a short period (1 h) of daytime sleep. METHODS: There were 16 participants, 8 men and 8 women, who volunteered to participate in this study. The study was conducted using a counterbalanced, double-blind, repeated measures design. At 1 h prior to drug administration, and at each of 7 h postdrug, performance measures (cognition, memory, balance, and strength) and subjective symptom reports were recorded. RESULTS: Zaleplon had a statistically significant (p < 0.05) negative impact on balance through the first 2 h postdose when compared with placebo. In addition, symptoms related to "drowsiness" were statistically more prevalent under zaleplon than under placebo through the first 3 h postdrug. Of the eight measures of cognitive performance, six were significantly negatively impacted in the zaleplon condition through 2 h postdose when compared with placebo, with one remaining significantly degraded through 3 h postdose. Zaleplon also had a significantly negative impact on memory at 1 h and 4 h postdose. CONCLUSIONS: Zaleplon (10 mg), when used as a daytime sleep aid, causes drowsiness (and related symptoms) up to 3 h postdose, and may impact task performance, especially more complex tasks, for at least 2-3 h postdose.     

Central effects of cinnarizine: restricted use in aircrew

HYPOTHESIS: Our aim was to establish the effects of cinnarizine, a drug used for the treatment of motion sickness, on daytime sleepiness and performance. METHODS: The effects of cinnarizine (15, 30, and 45 mg) were assessed on digit symbol substitution, tracking, vigilance, and on subjective and objective (daytime sleep latencies) sleepiness in six healthy volunteers between the ages of 20 and 34 yr (mean 27 yr) from 1.0 h prior to ingestion to 8.0 h after ingestion. The study was placebo-controlled and double-blind in a six-way, cross-over design. Promethazine (10 mg) was used as an active control. RESULTS: No effects of 15 mg cinnarizine were observed on performance. Sleep latencies were reduced at 3.5 and 5.0 h after ingestion, and the subjects as a group reported increased sleepiness at 5.0 and 6.5 h after ingestion. With 30 mg cinnarizine there was evidence of impaired performance at 5.0, 6.5, and 8.0 h after ingestion. Sleep latencies were not reduced, but the subjects as a group reported increased sleepiness 5.0 h after ingestion. With 45 mg cinnarizine there was evidence of impaired performance 5.0 h after ingestion. Sleep latencies were reduced at 5.0 and 6.5 h after ingestion, and the subjects as a group reported increased sleepiness 6.5 h after ingestion. Promethazine (10 mg) shortened sleep latencies from 2.5 to 5.0 h after ingestion, and the subjects as a group reported increased sleepiness overthis period. CONCLUSION: Cinnarizine is not free of central activity over the usual therapeutic dose range of 15 to 30 mg. It is contraindicated for motion sickness in aircrew involved in the control of aircraft. Caution should be exercised in the use of the drug by other aircrew who may be involved in tasks which demand continued attention.     

Cognitive performance following premature awakening from zolpidem or melatonin induced daytime sleep

BACKGROUND: The hypnotic zolpidem and the hormone melatonin were evaluated and directly compared for their effects on performance when subjects sleeping under their influence were prematurely awakened from daytime sleep. METHOD: Non-sleep deprived volunteers (eight men and five women) received single oral doses of 5 or 10 mg melatonin (Mel-5; Mel-10), 10 or 20 mg zolpidem (Zol-10; Zol-20), or placebo immediately before retiring at 13:00. Performance testing and subjective evaluations occurred prior to dosing and following forced awakening at 15:00, 2 h after dosing. RESULTS: Compared with placebo, on being awakened under Zol-20, significant performance decrements were prevalent on 9 of 10 cognitive tasks, including grammatical reasoning, mathematical processing, and word memory. Recovery required up to 6 h post-awakening for the more complex tasks. Loss of coordination and nausea were also present on awakening under Zol-20. On being awakened under Zol-10, significant but relatively less severe and shorter duration performance decrements occurred for 4 of the 10 tasks and recovered by 4 h post-awakening. Under Mel-5 or Mel-10, performance decrements seldom occurred and were considerably less severe, briefer, and less systematic than for zolpidem. CONCLUSION: Findings indicated that when operational personnel sleeping with the aid of either 10 or 20 mg zolpidem are prematurely awakened, it would be prudent to evaluate their general well-being and possible need for assistance prior to their being permitted to depart crew-rest or to perform tasks and duties. In contrast, we found little to no evidence of deteriorated well-being or need for assistance when awakened while sleeping under the influence of melatonin.     

Sleep-inducing pharmaceuticals: a comparison of melatonin, zaleplon, zopiclone, and temazepam

INTRODUCTION: Current military operations often require pharmaceutical methods to sustain alertness and facilitate sleep in order to maintain operational readiness. This study was designed to compare the sleep-inducing power of four medications. METHOD: There were 9 men and 14 women, ages 21-53 yr, who were assessed for psychomotor performance before and for 7 h after ingestion of a single dose of placebo, zaleplon 10 mg, zopiclone 7.5 mg, temazepam 15 mg, or time-released melatonin 6 mg. The experimental design was a double-blind crossover with counterbalanced treatment order. Subjects wore polysomnographic electrodes to record total sleep and sleep latency during 4-min periods with eyes closed immediately before and after each psychomotor test sequence. Subjective drowsiness was assessed by questionnaire. RESULTS: There were drug x trials interactions for zaleplon, zopiclone, and temazepam for total sleep, sleep latency, and subjective drowsiness. More sleep, shorter sleep latency, and more drowsiness occurred immediately after psychomotor testing compared to before testing for all medications. Melatonin did not cause any sleep prior to psychomotor testing sessions, but caused sleep and reduced sleep latency after psychomotor test sessions from 1 3/4 h to 4 3/4 h post-ingestion. CONCLUSIONS: The sleep-inducing power of the medications before psychomotor testing was zopiclone > zaleplon > melatonin > temazepam. The corresponding effect after psychomotor testing was zopiclone > melatonin > zaleplon > temazepam.     

Antihistamines and aircrew: usefulness of fexofenadine

INTRODUCTION: The aim of this study was to establish whether fexofenadine hydrochloride, an antihistamine, modulates daytime sleepiness or performance. METHODS: The effects of fexofenadine (120, 180, and 240 mg) on digit symbol substitution, tracking, and vigilance tasks, and on objective (multiple sleep latency test) and subjective sleepiness, were studied in six healthy volunteers (two males, four females, aged 20-34 [mean 26.5] yr) from 1 h pre-ingestion to 8 h post-ingestion. The study was placebo-controlled and double-blind with a six-way cross-over design. The centrally acting antihistamine, promethazine (10 mg), was used as an active control to confirm the sensitivity of the experimental procedures. RESULTS: There were no changes in performance or sleepiness with any dose of fexofenadine at any time, compared with placebo. Promethazine, compared with both placebo and fexofenadine, impaired performance on the digit symbol substitution task (2.5 h post-ingestion), vigilance task (2.5-5h post-ingestion) and tracking task (2.5-3.5 h post-ingestion), increased objective sleepiness (1.5-2.5 h post-ingestion) and subjective sleepiness (1.5-8h post-ingestion). CONCLUSION: Consideration may be given to the clinical use of currently licensed doses of fexofenadine (120-180 mg) by individuals involved in skilled activity. Fexofenadine may be potentially useful for aircrew.