Purpose: Despite conflicting experimental and clinical evidence, diphenylhydantoin continues to be used for the treatment of alcohol withdrawal seizures in emergency departments and alcohol detoxification centers. Our goal was to evaluate the effectiveness of intravenous diphenylhydantoin for prevention of alcohol withdrawal seizures in high-risk patients using a prospective, randomized, double-blind, placebo-controlled study design.
Patients and methods: Ninety alcoholic patients, enrolled within six hours of the initial alcohol-related seizure in a withdrawal episode, were randomly assigned to treatment with intravenous diphenylhydantoin (1,000 mg) or placebo. Seventy-one patients had a history of seizures during prior alcohol withdrawal episodes. Patients with a history of seizures unrelated to alcohol withdrawal were excluded. Drugs known to affect the seizure threshold or demonstrating cross-tolerance with alcohol were withheld. For each patient, the study endpoint was either (1) seizure recurrence or (2) a minimum 12-hour seizure-free observation period after completion of the study drug infusion.
Results: During the postinfusion observation period, six of 45 diphenylhydantoin-treated patients and six of 45 placebo-treated patients experienced at least one recurrent seizure. Equivalent diphenylhydantoin serum levels were measured in patients with and without subsequent seizures. There was no statistically significant difference between the response rates for the two treatments (p greater than 0.05). The 95% confidence interval for the difference in response probabilities was -14.0%, 14%.
Conclusion: When administered to non-epileptic patients within six hours of the onset of alcohol withdrawal seizures, intravenous diphenylhydantoin failed to show a significant benefit over placebo in the prevention of subsequent seizures. We suggest that the well-documented risks of intravenous diphenylhydantoin therapy outweigh the potential benefit in the short-term treatment of alcohol withdrawal seizures.