Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Overall adverse effects
Systematic review	830 people aged 60 years or over with insomnia	Adverse effects with any sedative hypnotic
RCT 4-armed trial	549 people with primary insomnia aged 65 years or older	Adverse effects 63% with zolpidem 56% with placebo Absolute results reported graphically
RCT 4-armed trial	549 people with primary insomnia aged 65 years or older	Central nervous system adverse effects 25% with zolpidem 14% with placebo Absolute results reported graphically	P <0.05	Effect size not calculated	placebo
RCT 6-armed trial	221 inpatients aged 61 to 94 years with chronic insomnia	Adverse effects 1/22 (5%) with zolpidem 5 mg 1/18 (6%) with zolpidem 10 mg 2/22 (9%) with zolpidem 20 mg 7/22 (32%) with zolpidem 30 mg 2/23 (9%) with placebo
RCT Crossover design	24 older volunteers	Severe adverse events 0/24 (0%) with placebo 4/24 (17%) with zolpidem 5 mg 2/24 (8%) with zolpidem 10 mg	Significance not assessed
RCT Crossover design	24 older volunteers	Withdrawals from adverse events 0/24 (0%) with placebo 1/24 (4%) with zolpidem 5 mg 2/24 (8%) with zolpidem 10 mg	Significance not assessed
RCT	205 people aged 65 to 87 years, mean age 70.2 years, with primary insomnia	Proportion of people with adverse effects 3 weeks 38% with zolpidem XR 6.25 mg daily for 3 weeks 40% with placebo Absolute numbers not reported	Significance not assessed
Rebound insomnia
RCT 4-armed trial	549 people with primary insomnia aged 65 years or older	Median sleep latency (change from baseline) 60 (+1.75) minutes with zolpidem 44 (–23.79) minutes with placebo Absolute results reported graphically	P <0.01	Effect size not calculated	placebo
RCT 4-armed trial	549 people with primary insomnia aged 65 years or older	Median subjective total sleep time (change from baseline) 300.00 (–8.57) minutes with zolpidem 317.50 (+22.98) minutes with placebo Absolute results reported graphically	P <0.001	Effect size not calculated	placebo