A Cochrane review included three trials (573 participants) comparing phenobarbitone with placebo or no treatment. In the two trials with adequate allocation concealment, death was more common in the anticonvulsant group (RR 2.0; 95% CI 1.20 to 3.33; fixed effect model, n=388). In all three trials, phenobarbitone compared with placebo or no treatment was associated with fewer convulsions (RR 0.30; 95% CI 0.19 to 0.45; fixed effect model).
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions, e.g. different doses of phenobarbitone and use of additional drugs) and by imprecise results (few patients and wide confidence intervals).