Contraindications to phenytoin in emergency department patients with seizures

The objective of this study was to determine what contraindications to phenytoin exist in Emergency Department (ED) patients with a medical history of seizures. We conducted a retrospective chart review using ED medical records from 2005 at two network health care EDs. We identified potential patients through ICD-9 (International Classification of Diseases, Ninth Revision) codes, selected only adult patients with a prior documented history of seizures, and reviewed these charts. From 201 charts reviewed, the three most common antiepileptic drugs taken by patients were: phenytoin (38%), levetiracetam (17%), and valproic acid (15%). For absolute contraindications to phenytoin, 4.5% of seizure patients had a known hypersensitivity to phenytoin and 1.5% were pregnant; however, no pregnant patients were taking phenytoin and only 1 person with hypersensitivity to phenytoin was taking phenytoin. For relative contraindications, 6% of seizure patients had liver disease, 8% had kidney disease, 9% had alcohol use/dependence, and 16% had diabetes. However, 55% of those with liver disease, 44% with kidney disease, 77% with alcohol use/dependence, and 53% with diabetes were currently taking phenytoin. Very few seizure patients in the ED have absolute contraindications to the use of phenytoin, and most with absolute contraindications are taking other antiepileptic drugs. Conversely, a greater proportion of seizure patients have relative contraindications and many are continuing to use phenytoin.