Kalviainen 1998

Methods	Randomised, double‐blind, placebo‐controlled, two‐treatment parallel‐group study. Two treatment arms: one PCB, one TGB. Participants randomly assigned using computer‐generated sequence. Treatment period: 22 weeks (six‐week run in period, 12‐week fixed‐dose period, four‐week termination period)
Participants	Multi‐centre study (11 centres in Europe—one each in Denmark and Sweden, two in Finland and seven in UK 154 participants with drug‐resistant partial epilepsy were randomly assigned (90 male), aged 17 to 71 years 77 were randomly assigned to placebo and 77 to 30 mg/d tiagabine Participants already taking one to three background AEDs Median four‐weekly baseline seizure frequency: placebo = 10.5, tiagabine = 12.2 Cognitive and quality of life effects were assessed on a subset of 43 individuals
Interventions	Group one: PCB Group two: TGB 30 mg/d TDS
Outcomes	50% responder rates Treatment withdrawal Adverse effects Cognitive effects Quality of life
Notes	No participants were excluded from analysis. 29 people withdrew from the study: 21 receiving tiagabine and eight receiving placebo
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Used a computer‐generated allocation sequence
Allocation concealment (selection bias)	Low risk	Used sequentially allocated sealed packages
Blinding (performance bias and detection bias) All outcomes	Low risk	Used identical packaging and medication
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attriition rates reported and intention‐to‐treat analysis employed
Selective reporting (reporting bias)	Low risk	All outcomes reported in methods section were reported in text; however, no protocol available for comparison of outcomes