Bourgeois 1993

Methods	Randomised, double‐blind, placebo‐controlled, parallel‐group study Randomisation was by permuted block. The randomisation was done at Wallace Laboratories and no‐one at the clinical sites was involved in the allocation. Medication (or placebo) was provided in identical packages. 4‐week treatment period included 3‐day titration period.
Participants	Multicenter study 64 participants were randomised (38 male), aged 17 to 51 years. 30 participants were randomised to felbamate and 34 to placebo. Mean 4‐weekly baseline seizure frequency: felbamate group: simple partial seizure = 4.9, complex partial seizure = 14.1, partial‐onset seizures with generalisation = 0.4 placebo group: simple partial seizure = 5.9, complex partial seizure = 7.6, partial‐onset seizures with generalisation = 0.3 Number of other AEDs: felbamate group = 3‐9; placebo group = 2‐9
Interventions	Add‐on felbamate or placebo Felbamate was titrated from 1600 mg/d to 3600 mg/d over a period of 3 days and maintained on 3600 mg/d or the maximum tolerated dose, not to exceed 3600 mg/d
Outcomes	The mean rank of seizure frequency Time to 4th seizure Adverse effects
Notes	Of the 64 participants randomised to the double‐blind phase, 3 were excluded from the analysis of the mean rank of seizure frequency. All 64 participants were evaluated for the analyses of time to 4th seizure and adverse effects.
Risk of bias
Bias	Authors' judgement	Support for judgement
Selective reporting (reporting bias)	Low risk	The outcomes mentioned in the methods were reported.
Random sequence generation (selection bias)	Low risk	Quote: "they were randomised to the felbamate or placebo treatment groups". We contacted the study author and the reply was as follows: "I think that randomisation was by permuted block, but I do not remember for sure".
Allocation concealment (selection bias)	Low risk	We contacted the study author and the reply was as follows: "The randomisation was done at Wallace Laboratories and no one at the clinical sites was involved in the allocation."
Blinding of participants and personnel (performance bias) All outcomes	Low risk	We contacted the study author and the reply was as follows: "Medication (or placebo) was provided by Wallace Laboratories to the clinical sites in identical packages. The study was double‐blind. The patients as well as the doctors and nurses did not know whether the treatment was felbamate or placebo."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "double blind". Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	3/64 were excluded from the analysis of the mean rank of seizure frequency. All 64 participants were evaluated for the analyses of time to 4th seizure and adverse effects