Trimethoprim-sulfamethoxazole Induced Pancytopenia: A Common Occurrence but A Rare Diagnosis

Trimethoprim-sulfamethoxazole (TMP-SMX) is a bacteriostatic antimicrobial medication used for the treatment of a variety of infections and has many reported skin and hematologic side effects. Due to the easy availability and cost effectiveness, TMP-SMX is one of the medications commonly used for treatment of skin and soft tissue in patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. One of the rare hematologic manifestations of TMP-SMX is pancytopenia, which is a reduction in all cell lines. In this case report, we are documenting a case of pancytopenia due to severe drug reaction to TMP-SMX in a 70-year-old female after two weeks of medication use. Upon initial stabilization she underwent a thorough workup and was subsequently diagnosed with severe drug-induced pancytopenia. Detailed history, early diagnosis, prompt discontinuation of the offending medication along with supportive care remain the mainstay of treatment in the management of TMP-SMX induced pancytopenia.