Heller 1995

Methods	Parallel study design, outpatient setting Study conducted at two centres in the UK Random list generated using random permuted blocks Allocation concealed using sealed opaque envelopes Unblinded
Participants	Adults with newly diagnosed epilepsy (2 or more untreated partial or generalised tonic‐clonic seizures in the 12 months preceding the trial) Number randomised: PHT = 63; SV = 61 53 participants (43%) with partial epilepsy. 62 (48%) men Mean age (range): 33 (14‐72) years Range of follow‐up (months): 1‐91
Interventions	Monotherapy with PHT or SV Median daily dose achieved: PHT: 300 mg/day, SV: 800 mg/day
Outcomes	Time to first seizure recurrence after start of therapy Time to 12‐month remission from all seizures Adverse events and withdrawal due to adverse events
Notes	IPD provided for all outcomes of this review
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation list generated using permuted blocks of size 8 or 16 with stratification for centre, seizure type and presence of neurological signs
Allocation concealment (selection bias)	Low risk	Allocation concealed via 4 batches of concealed opaque envelopes
Blinding of participants and personnel (performance bias) All outcomes	High risk	Unblinded, authors state masking of treatment would not be “practical” and would have “introduced bias due to a very large drop‐out rate”
Blinding of outcome assessment (detection bias) All outcomes	High risk	Unblinded, authors state masking of treatment would not be “practical” and would have “introduced bias due to a very large drop‐out rate”
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition rates reported, all randomised participants analyses from IPD provided (see footnote 2)
Selective reporting (reporting bias)	Low risk	All outcomes reported or calculated with IPD provided (see footnote 2)
Other bias	Low risk	No other bias detected