Stevens-Johnson Syndrome in a Patient on Concomitant Treatment with Levetiracetam and Trimethoprim/Sulfamethoxazole

BACKGROUND Trimethoprim/sulfamethoxazole and levetiracetam are commonly prescribed medications in the treatment of infections and seizures, respectively. Despite their known efficacy, each has a reputation for triggering severe and sometimes life-threatening cutaneous adverse drug reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis. Although the mechanism of such cutaneous adverse drug reactions cannot be fully explained, it is thought to be a type IV T cell and NK cells-mediated hypersensitivity reaction that leads to keratinocyte apoptosis and epidermal necrosis. It is also thought that cutaneous adverse drug reactions are also linked to a patient's genetic predispositions, especially the human leukocyte antigens profiles and the N-acetyl transferase 2 phenotypic variation. CASE REPORT We describe a case of Stevens-Johnson syndrome in a severely ill 51-year-old man who was treated in an outside health care facility simultaneously with Trimethoprim/sulfamethoxazole and levetiracetam. The patient presented to our Emergency Department with Stevens-Johnson syndrome believed to possibly be related to the combination of these 2 agents. CONCLUSIONS The concomitant use of Trimethoprim/sulfamethoxazole and levetiracetam might have been responsible for heightening the potential of these 2 medications to trigger an unfortunate adverse drug reaction, but no formal culprit was able to be identified and no in vivo study was performed, due to ethical considerations. Thus, through this case report we strive to increase awareness of the potential risk of simultaneously prescribing these 2 medications.