Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Overall adverse effects
RCT 4-armed trial	549 people with primary insomnia aged 65 years and over	Treatment-emergent adverse events 56% with zaleplon 5 mg 59% with zaleplon 10 mg 56% with placebo
RCT 3-armed trial	422 people aged 65 years or over with primary insomnia for 3 months or more	Treatment-emergent adverse effects 68 (48%) with zaleplon 5 mg 59 (50%) with zaleplon 10 mg 74 (51%) with placebo
Rebound insomnia
RCT 4-armed trial	549 people with primary insomnia aged 65 years and over	Median subjective total sleep time (change from baseline) first night after discontinuing medication 300.00 (–8.57) minutes with zaleplon 10 mg 317.50 (+22.98) minutes with placebo	P <0.05 for zaleplon 10 mg v placebo	Effect size not calculated	placebo
RCT 3-armed trial	422 people aged 65 years or over with primary insomnia for 3 months or more	Proportion of people with rebound insomnia 17/136 (13%) with zaleplon 10 mg 6/130 (5%) with placebo	P = 0.03 for zaleplon 10 mg v placebo	Effect size not calculated	placebo