Abstracts

Rationale: Rationale: The American Academy of Neurology has stated that generic substitution of antiepileptic drugs (AEDS) should not be undertaken without the prescribing physician s approval. The safety concern for this statement has been to prevent breakthrough seizures. The case discussed herein raises an additional concern regarding an adverse effect of generic substitution, which can also be a severe confounder for adequate treatment of an epilepsy patient. This confounder is an allergic reaction to the generic excipient ingredients in a tablet which also contains a potentially allergenic AED. Methods: Methods: Case presentation-the patient is a 50 year-old Asian woman with a history of localization related epilepsy manifested as complex partial seizures and secondary generalized seizures beginning at age 30 years. Routine EEG showed left temporal spikes and MRI was unrevealing. She was seizure free for seven years taking brand name Lamictal at 500 mg per day. Generic lamotrigine became available during one of her long-term prescription periods and she was changed to generic lamotrigine by the insurance company at the pharmacy and the prescribing physician was not notified. The patient reported that three days after changing to generic lamotrigine at the same daily dose she developed pruritic rash on scalp, neck and torso. The patient was emergently examined by the prescribing physician and found to have confluent red macular rash in the same areas. This was thought to be a drug-related allergic rash, possibly associated with the generic lamotrigine formulation since no other medications had been changed. Due to concern about the risk of seizures, the patient did not want to discontinue lamotrigine. Therefore, she was immediately changed back to the brand name Lamictal (after emergency insurance authorization) and the rash resolved within two days. Results: Results: The patient had an allergic reaction to the generic formulation of lamotrigine, but no allergy to Lamictal either before or after the allergy to the generic tablet. This isolates an unknown generic excipient as the allergen, rather than lamotrigine. Conclusions: Conclusion: The forced use of generic formulations by an insurance company could lead to incorrect assumptions about the allergic profile and best treatment approaches for a patient with epilepsy. In this case, the patient was well controlled on brand name Lamictal and was forced by circumstances beyond her control to change to generic lamotrigine. Many treating physicians might not have rechallenged her with the brand name even though she had a long history of seizure freedom due to the concern that she may have developed a lamotrigine allergy. This case demonstrates that it may be in the best interest of the patient to leave well enough alone.