Crawford 2001

Methods	Randomised, double‐blind, placebo‐controlled, cross‐over study, based on a response‐dependent design. Two treatment arms: one TGB, one PCB. Participants randomly assigned to one of two sequences. TGB started during screening phase at 12 mg/d QID. Seven‐week double‐blind treatment period during which participants continued on TGB or crossed over to PCB arm
Participants	Multi‐centre study (five centres: two in UK, two in The Netherlands and one in Denmark) 44 participants with drug‐resistant partial epilepsy were randomly assigned (30 male), aged 18 to 53 years Participants already taking one to three background AEDs Median baseline seizure frequency = 2.7/wk.
Interventions	Group one: PCB Group two: TGB (optimal dose 64 mg/d) Mean daily dose for all randomly assigned participants was 46 mg during the double‐blind phase
Outcomes	50% responder rates Median percentage reduction in four‐weekly seizure rate Adverse events
Notes	From the 44 people randomly assigned to the double‐blind phase, seven were excluded from the intent‐to‐treat analysis. All participants were evaluated for adverse events
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants randomly assigned in a 1:1 ratio at each centre to one of two sequences. No further details on how the sequences were generated
Allocation concealment (selection bias)	Low risk	Sequentially allocated sealed packages used
Blinding (performance bias and detection bias) All outcomes	Low risk	Used identical packaging and medication
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition 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 is available for comparison of outcomes