Prophylactic use of antiepileptic drugs (AEDs) in patients admitted with aneurysmal subarachnoid hemorrhage (SAH) is common practice; however, the impact of this treatment strategy on in-hospital complications and outcome has not been systematically studied. The goal in this study was twofold: first, to describe the prescribing pattern for AEDs in an international study population; and second, to delineate the impact of AEDs on in-hospital complications and outcome in patients with SAH.

The authors examined data collected in 3552 patients with SAH who were entered into four prospective, randomized, double-blind, placebo-controlled trials conducted in 162 neurosurgical centers and 21 countries between 1991 and 1997. The prevalence of AED use was assessed by study country and center. The impact of AEDs on in-hospital complications and outcome was evaluated using conditional logistic regressions comparing treated and untreated patients within the same study center.

Antiepileptic drugs were used in 65.1% of patients and the prescribing pattern was mainly dependent on the treating physicians: the prevalence of AED use varied dramatically across study country and center (intraclass correlation coefficients 0.22 and 0.66, respectively [p < 0.001]). Other predictors included younger age, worse neurological grade, and lower systolic blood pressure on admission. After adjustment, patients treated with AEDs had odds ratios of 1.56 (95% confidence interval [CI] 1.16–2.10; p = 0.003) for worse outcome based on the Glasgow Outcome Scale; 1.87 (95% CI 1.43–2.44; p < 0.001) for cerebral vasospasm; 1.61 (95% CI 1.25–2.06; p < 0.001) for neurological deterioration; 1.33 (95% CI 1.01–1.74; p = 0.04) for cerebral infarction; and 1.36 (95% CI 1.03–1.80; p = 0.03) for elevated temperature during hospitalization.

Prophylactic AED treatment in patients with aneurysmal SAH is common, follows an arbitrary prescribing pattern, and is associated with increased in-hospital complications and worse outcome.