North 1983.

Methods	Random allocation, double‐blind design
Participants	Participants with a supratentorial tumor, allocated to 1. Phenytoin: Meningioma (n=10), metastasis (n=6), sellar tumor (n=10), glioma (n=16) 2. Placebo group: meningioma (n=9), metastasis (n=7), sellar tumor (n=7), glioma (n=16)
Interventions	Phenytoin 250 mg twice daily iv, then 100 mg orally three times daily x 12 months. Serum levels once a month for inpatients, bimonthly for outpatients. Doses were adjusted accordingly
Outcomes	18 seizures in group treated with phenytoin, 26 in placebo group. By time‐to‐event analysis, group treated with PHT had significantly fewer seizures between days 7‐72 of study. The maximal protective effect was in postop week 2
Notes	Because 65% of seizures occurred within 3 mo from surgery, authors recommended prophylaxis for 2‐3 mo, starting 1 wk before surgery. Focal seizures in 7/9 pts with therapeutic levels
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	D ‐ Not used