Three-day phenytoin prophylaxis is adequate after subarachnoid hemorrhage

Phenytoin (PHT) is widely administered after subarachnoid hemorrhage, often for several weeks or months. In addition to known side effects, PHT use has been correlated with cognitive disability and poor outcome. To reduce the rate of PHT complications, we converted from a multi-week prophylactic regimen to a 3-day course of treatment. This study evaluates the changes in seizure rates and adverse events.

From July 1998 to June 2002, 453 patients with spontaneous subarachnoid hemorrhage were treated. In the first 9 months, 79 patients were administered PHT until discharged from the hospital, unless a drug reaction occurred first. In the last 39 months, PHT was discontinued 3 days after admission (370 patients), unless there was a history of epilepsy (four patients). This study represents a retrospective analysis of prospectively collected data, with follow-up periods of 3 to 12 months after discharge.

The 3-day PHT regimen produced a statistically significant reduction (P = 0.002) in the rate of PHT complications. In the first period, seven (8.8%) out of 79 patients experienced a hypersensitivity reaction, compared with two (0.5%) out of 370 patients in the second period. The percentage of patients having seizures, both short- and long-term, did not change significantly. In the first period, the seizure rate during hospitalization was 1.3%; in the second period, it was 1.9% (P = 0.603). At an average follow-up period of 6.7 months, three (5.7%) out of 53 survivors in the first period experienced a seizure (including those who had a seizure during hospitalization). In the second period, 12 (4.6%) out of 261 survivors experienced a seizure at an average follow-up period of 5.4 months (P = 0.573).

A 3-day regimen of PHT prophylaxis is adequate to prevent seizures in subarachnoid hemorrhage patients. Drug reactions are significantly reduced, but seizure rates do not change. Short-term PHT administration may be a superior treatment paradigm.