Steiner 1999

Methods	Randomised, double‐blind, multicentre trial conducted in the UK 2 treatment arms: LTG and PHT
Participants	Participants aged 14‐75 years with two or more partial, secondarily generalised, or primary generalised tonic‐clonic seizures Number randomised: PHT = 95, LTG = 86 101 male participants (56%) 90 participants with partial epilepsy (50%) Mean age (range): 34 (13‐75 years)
Interventions	Monotherapy with LTG or PHT Titrated for 2 weeks to a target dose of LTG = 150 mg/d, PHT = 300 mg/d Range of follow‐up: 0‐15 months
Outcomes	Percentage of participants remaining on treatment Percentage of participants remaining seizure free in the last 24 and last 16 weeks of treatment Number of seizures (percentage change from baseline) in the last 24 weeks and 16 weeks of treatment Time to first seizure after the first 6 weeks of treatment (dose‐titration period) Time to discontinuation Incidence of adverse events and adverse events leading to discontinuation Quality of Life according to the Side Effects and Life Satisfaction (SEALs) inventory
Notes	IPD provided by trial sponsor Glaxo Smith Kline for time to treatment withdrawal, time to first seizure and time to six‐month remission
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation was stratified according to seizure type, no further information provided
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	All participants, personnel and outcome assessors involved in the trial were blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	All participants, personnel and outcome assessors involved in the trial were blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition rates reported, ITT approach, all randomised participants analysed from IPD provided (see footnote 2)
Selective reporting (reporting bias)	Low risk	Protocol provided. All outcomes reported or calculated with IPD provided (see footnote 2)
Other bias	Low risk	None identified