Table 1

 Characteristics of studies included in review of Z drugs (a more detailed version of this table is in appendix 3)

Study identifier, year, country (No of sites)NoWomenMean (SD) age (years)DrugRecruitmentBaseline PSG (subjective) sleep latencyDesignPatient typeOutcome
EFC4529, 2004, US (29), Canada (5), Australia (6)21258%44 (13)Zolpidem MR 12.5 mgCommunityIntervention: 41.7 (61.4); placebo: 43.8 (62.0) Phase II multicentre randomised double blind placebo controlled parallel group OutpatientsWake after sleep onset PSG, sleep latency PSG, No of awakenings PSG, No of awakenings subjective, sleep latency subjective, total sleep time PSG
EFC4530, 2004, Argentina (5), Canada (7), France (4), Germany (6), Mexico (2), US (16)20557%70 (5)Zolpidem MR 6.25 mgCommunityIntervention: 36.9 (56.0); placebo: 35.7 (62.9)Randomised multicentre double blind placebo controlledOutpatientsWake after sleep onset PSG, sleep latency PSG, No of awakenings PSG, No of awakenings subjective, sleep latency subjective, total sleep time PSG
LSH17, 1988, US (4)7564%38Zolpidem MR 10 mg and 15 mg CommunityIntervention: zolpidem 10 mg: 35.8 (38.4); zolpidem 15 mg: 47.0 (61.0); placebo: 49.9 (70.4)Double blind parallel group OutpatientsSleep latency PSG, Sleep efficiency PSG, No of awakenings PSG, sleep latency subjective, total sleep time subjective, No of awakenings subjective, sleep quality subjective.
LSH, 1992, US (6)14556%45Zolpidem (10 mg and 15 mg) CommunityIntervention: zolpidem 10 mg (65.1); zolpidem 15 mg (75.9); placebo: (58.2)Double blind parallel group OutpatientsSleep latency subjective, total sleep time subjective, No awakenings subjective, sleep quality subjective
IV LSH, NR, NR75NRNRZolpidem 10 mg and 15 mgCommunityIntervention: zolpidem 10 mg: 35.8 (57.0); zolpidem 15 mg: 47.0 (61.0); placebo: 49.9 (70.4)Multicentre double blind randomised placebo controlled parallel group trialOutpatientsSleep latency PSG, sleep latency subjective, Sleep efficiency PSG
204-EU, 1997, Spain (4), France (3), Belgium (3), Netherlands (1)130NRNRZaleplon 10 mg and 20 mg vs. zolpidem 10 mgCommunityIntervention: zaleplon 10 mg: 40.4; zaleplon 20 mg: 48.0; zolpidem 10 mg: 47.8; placebo: 48Phase II, multicentre, double blind comparative parallel group efficacy, safety, tolerance, outpatient and sleep laboratory trialOutpatientsSleep latency PSG
Trial 301, 1998, US (27)58658.4%41.8Zaleplon 5 mg, 10 mg and 20 mg; zolpidem 10 mg CommunityIntervention: zaleplon 5 mg: 81.5; zaleplon 10 mg: 77.7; zaleplon 20 mg: 72.5; zolpidem 10 mg: 70.5; placebo: 80.4Randomised placebo controlled parallel group multicentre double blind trialOutpatientsSleep latency PSG.
Trial 307, 1998, US and Canada (39)63760.6%43Zaleplon 10 mg/10 mg, 10 mg/20 mgCommunityIntervention: zaleplon 10 mg/10 mg: 79.8; zaleplon 10 mg/20 mg: 81.9; placebo: 77.93Randomised placebo controlled parallel group multicentre double blind trialOutpatientsSleep latency PSG
Trial 303, 1998, Europe and Canada57464.4%42.8Zaleplon 5 mg, 10 mg, 20 mg, zolpidem 10 mgCommunityIntervention: zaleplon 5 mg: 66.0; zaleplon 10 mg: 57.0; zaleplon 20 mg: 55.0; zolpidem 10 mg: 64.0; placebo: 58.0Randomised placebo controlled parallel group multicentre double blind trialNRSleep latency PSG
Trial 306, 1998, US42264.4%72.5Zaleplon 5 mg and 10 mg CommunityIntervention: zaleplon 5 mg: 62.1; zaleplon 10 mg: 70.7; placebo: 68.0Prospective randomised double blind placebo controlled five arm parallel group multicentre trialNRSleep latency PSG
190-049, 2003, US and Canada (69)79163.2%44.1Eszopiclone 3 mgNRIntervention: NR; control: NRMulticentre randomised trialNRSleep latency subjective, total sleep time subjective, wake after sleep onset subjective
190-047, 2003, USA (48), Canada (2)29265.9%70.7Eszopiclone 2 mg NRIntervention: NR; control: NRMulticentre randomised trialNRSleep latency PSG, sleep efficiency PSG, wake after sleep onset PSG
190-048, 2003, US and Canada (32)23457.7%72.3Eszopiclone 1 mg and 2 mgNRIntervention: NR; control: NRMulticentre randomised trialNRSleep latency subjective, total sleep time subjective

NR=not reported; MR=modified release; PSG=polysomnographic.

*Trial 307-1998 had two intervention arms: (i) zaleplon 10 mg for 14 days with outcomes measured at 7 days and 14 days compared with placebo and (ii) zaleplon 10 mg for 7 days followed by 20 mg for 7 days with outcomes measured at 7 days and 14 days compared with placebo; in both studies we used last measurement at 14 days and averaged dose at 15 mg as best approximation for study arm using 10 mg followed by 20 mg zaleplon.