Anhut 1994.

Study characteristics
Methods	Randomised, double‐blind, placebo‐controlled, parallel‐group study (conducted at 24 centres in Europe, Canada, South Africa and Australia) 3 treatment arms: 1 placebo and 2 gabapentin Prospective prerandomisation baseline period: 12 weeks Treatment period: 12 weeks
Participants	Adults with drug‐resistant focal epilepsy Total randomised: 272 109 to placebo; 111 to gabapentin 900 mg; 52 to gabapentin 1200 mg 56% men Age range: 12–67 years Other AEDs: ≤ 2 Median baseline seizure frequency per 28 days: 10.2 (range 0.5–634.3)
Interventions	Gabapentin 900 mg/day Gabapentin 1200 mg/day Placebo All tablets and packaging were identical in appearance.
Outcomes	Proportion with a 50% reduction in seizure frequency Response ratio (= (T – B)/(T + B) where T = number of seizures during the treatment period and B = number of seizures in the baseline period) Adverse effects
Notes	27 participants excluded from published analyses: 10 from placebo group; 15 from gabapentin 900 mg group; 2 from gabapentin 1200 mg group Additional unpublished data allowed the inclusion of participants excluded despite completing the treatment phase with adequate seizure data. The following participants contributed to the best‐case and worst‐case sensitivity analyses in this review: placebo: 7; gabapentin 900 mg: 9; gabapentin 1200 mg: 2.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random permuted blocks to generate sequence for randomisation.
Allocation concealment (selection bias)	Low risk	Allocated sequentially, sealed, numbered packages.
Blinding (performance bias and detection bias) All outcomes	Low risk	Tablets and packaging identical in appearance.
Incomplete outcome data (attrition bias) All outcomes	High risk	'As treated' analysis. Disproportionate numbers excluded across groups: 13 in placebo: 17 in gabapentin 900 mg: 2 in gabapentin 1200 mg, some excluded despite completing treatment phase. Exclusions not included in published analyses.
Selective reporting (reporting bias)	Low risk	Seizure diary for all groups, same outcomes. Published reports include all prespecified expected outcomes.
Other bias	High risk	Trial sponsored by Parke Davis. Study appeared free of other sources of bias.