Abstracts

Antiepileptic drugs (AEDs) with aromatic ring structures such as phenytoin, carbamazepine, and oxcarbazepine are known to cause allergic rashes in 4-10% of patients within the first month of treatment. Although the rash of a serious hypersensitivity reaction occurs in 1-4 in 10,000, rash is a major reason for discontinuing these drugs. Lamictal introduced in the 1990s has also been associated with a rash in the first few months. The incidence however has declined with slow titration and a serious hypersensitivity reaction is also uncommon.
Since the introduction of levetiracetam, this broad spectrum AED offers an effective substitute for those who develop benzene ring related rashes as well as lamictal rashes. Levetiracetam is well tolerated, is rarely associated with a rash, and avoids hepatic metabolism and multiple drug-drug interactions. In addition, it can be utilized effectively for sudden oral loading. Adult and pediatric patients who developed benzene ring or lamictal associated rashes, were loaded with levetiracetam as a substitute AED to prevent breakthrough seizures and avoid worsening rash while limiting pharmacologic and metabolic complications. We report 2 adults and 3 children who developed AED associated rashes. These medications were abruptly stopped and levetiracetam was immediately introduced at a full maintenance dose without seizures occurring; 3 grams in the adult cases and 1 gram in the pediatric cases. One young adult remains seizure free three years later after having a drug rash to phenytoin and oxcarbazepine. The other young adult tolerated levetiracetam substituting for lamictal for partial onset epilepsy with infrequent breakthrough seizures. The three children had partial onset epilepsy and rashes to oxcarbazepine (2) and carbamazepine (1). One patient remained seizure free on the initial dose, while two patients required a dosage adjustment to 1500 mg per day and now are seizure free for greater than one year. In conclusion, we propose that levetiracetam is an effective broad spectrum medication which may be substituted for AED related rashes. Levetiracetam offers a means for rapid oral loading without fear of worsening rash or harmful pharmacological or metabolic interactions.