Lim 1986.

Methods	Double‐blind RCT of parallel design
Participants	25 participants on a general medical ward, experiencing at least 2 leg cramps per week
Interventions	Nightly quinine sulphate (300 mg) or placebo for 2 weeks (or less if discharged earlier)
Outcomes	Cramp days, cramp intensity, adverse events
Notes	Poorly designed study with no mention of number of participants in each group. Scanty data also
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Each volunteer was randomly allocated to receive either 300 mg quinine or a placebo..." Comment: no description of randomisation protocol
Allocation concealment (selection bias)	Unclear risk	No mention of how allocation may have been concealed
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No details regarding methods of blinding are provided
Incomplete outcome data (attrition bias) All outcomes	High risk	Impossible to assess as no mention of number of participants in each group nor of how many actually completed the trial
Selective reporting (reporting bias)	Low risk	Both the intended outcome measures were addressed in the results and analysis
Other bias	High risk	Participants were recruited from a general medical ward as inpatients. Some were discharged before the 2‐week follow‐up