Li 2000.

Study characteristics
Methods	Active‐controlled, parallel‐group, double‐blind randomised controlled trial with a third group receiving sulthiame openly No historical baseline period, six‐month treatment phase
Participants	Participants with generalised tonic‐clonic seizures who had experienced a seizure within three to six months of the study start date Number of participants randomly assigned: 146 Number of participants in each group: intervention group: 32 (18 [56%] males and 14 [44%] females); control group: 32 (17 [53%] males and 15 [47%] females); open group: 82 (57 [70%] males and 25 [30%] females) Mean (SD) age, years: intervention group: 29.53 (15.09); control group: 34.91 (15.12): open group: 27.69 (16.76)
Interventions	Sulthiame (100 to 200 mg/d) versus phenytoin (100 mg TDS)
Outcomes	Adverse effects Treatment response defined as Markedly improved: > 75% decrease in seizure frequency Effective: 51% to 75% decrease in seizure frequency Improved: 26% to 50% decrease in seizure frequency Invalid or worsening: < 25% reduction in seizure frequency Laboratory tests prestudy and poststudy Blood count Liver function Kidney function ECG EEG
Notes	This paper provides no information regarding participants withdrawing from the trial after randomisation. All participants were subsequently included in the analysis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Method of randomisation not stated. High proportion of males versus females in open group
Allocation concealment (selection bias)	High risk	Method of allocation concealment not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Method of blinding not stated
Blinding of outcome assessment (detection bias) All outcomes	High risk	Method of blinding not stated
Incomplete outcome data (attrition bias) All outcomes	High risk	No data provided on participants withdrawing from treatment
Selective reporting (reporting bias)	High risk	No data on proportion of participants with a reduction in seizure frequency of 50% or greater, proportion of participants seizure free at 12 months or quality of life scale scores. Data provided on adverse effects include blinded and unblinded participants. It is unclear whether data provided on adverse effects is on number of events or number of participants experiencing an adverse effect.
Other bias	High risk	Incomplete information on inclusion and exclusion criteria and on combination of treatment and open groups when analysis of adverse effects was performed; separate data for the intervention group alone not provided