Lee 1991.

Methods	Single‐blind, parallel group RCT, set in Taiwan
Participants	31 cirrhotic participants with an average of over 3 muscle cramps per week
Interventions	4‐week run‐in period, followed by a 4‐week treatment period of either quinidine sulphate 200 mg twice‐daily or placebo twice‐daily
Outcomes	Cramp number, adverse events
Notes	Study conducted on an outpatient basis in Taiwan. 31 participants (mean age 62 years) completed the study. 84% participants were men
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "...were allocated, using a table of random numbers." Comment: probably done
Allocation concealment (selection bias)	Unclear risk	No mention of how allocation was conveyed to the investigators, though as this was a single‐blinded study, concealment may not have been attempted at all
Blinding (performance bias and detection bias) All outcomes	High risk	Quote: "Patients were not aware of which drug was being prescribed, but physicians were." Comment: single‐blinded study
Incomplete outcome data (attrition bias) All outcomes	Low risk	31 out of 43 participants completed the study and withdrawals are accounted for (excluded due to low cramp frequency or poor record keeping) and were excluded before randomisation
Selective reporting (reporting bias)	Low risk	All intended outcome measures are addressed in the results
Other bias	Low risk	Except for the lack of double‐blinding counted above, nil else significant