Cefoperazone induced gastrointestinal bleeding

Cefoperazone is a beta-lactam antibiotic which is frequently used in treating a variety of gram positive and gram negative infections. The chemical structure of cefoperazone contains a side chain of N-methylthiotetrazole which can inhibit vitamin K metabolism resulting in hypoprothombinemia. We report a case of cefoperazone induced coagulopathy manifesting as gastrointestinal bleeding. A Naranjo assessment score of 5 was obtained, indicating a probable relationship between the patient’s coagulation function disorder and her use of the suspect drug.