Study	Reason for exclusion
Baltodano 1988	This was an observational study where participants already on quinine were started on verapamil instead, and seen to improve
Coppin 2005	The focus of this RCT was on the cessation of quinine and effect of exercise
Morl 1980	The active treatment in this RCT comprised quinine with aminophylline. The effect of quinine alone could therefore not be ascertained
Sandoval 1980	This Spanish paper was translated into English. There was no evidence of randomisation and all cramps were treated with hypertonic saline, meaning that quinine was not given alone. Also the outcome measured was the number of dialysis sessions affected by cramp rather than the cramp number itself
Wessely 1984	The active treatment in this RCT of haemodialysis patients comprised quinine with aminophylline. The effect of quinine alone could therefore not be ascertained

RCT: randomised controlled trial