El‐Hazmi 1998.

Study characteristics
Methods	Double‐blind, randomised, placebo‐controlled parallel trial
Participants	Age: two groups; 3 ‐ 6 years and 7 ‐ 12 years, 50 males and 37 females. 79 were Hb SS and 8 were Hb Sß thalassemia
Interventions	48 received piracetam orally 160 mg/kg/day during follow up and 39 matched placebo. During crises intravenous infusion of 300mg piracetam or placebo /kg/day
Outcomes	Severity Index (SI) a composite measure of biochemical investigations, signs symptoms and other markers: Hb level, reticulocyte cytopenia, bilirubin level, LDH, number of severe painful crises/year, stroke/deep venous thrombosis, interstitial lung disease, cardiomyopathy, gallstones, papillary necrosis, aseptic necrosis, impotence, short stature.
Notes	This trial included the use of a 'rescue medication' of piracetam administered intravenously.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Low risk	Adequate.