Idiosyncratic Drug-Induced Neutropenia Following Pantoprazole, Moxifloxacin Hydrochloride, and Rifabutin Treatment for Helicobacter pylori: A Case Report

Idiosyncratic drug-induced neutropenia (IDIN) is a rare but potentially life-threatening condition characterized by immune-mediated neutrophil destruction. We present the case of a 45-year-old female who developed severe neutropenia following a 14-day <i>Helicobacter pylori</i> treatment regimen containing pantoprazole, moxifloxacin hydrochloride, and rifabutin. The patient initially presented with a one-week history of fever, chills, and myalgias, with laboratory findings revealing leukopenia and thrombocytopenia. Based on the temporal relationship between medication use and symptom onset, drug-induced neutropenia was suspected. Further follow-up and workup were completed, and the patient's symptoms resolved within one week of stopping the treatment regimen. Repeat bloodwork at this time also demonstrated recovery of her white blood cell count, further supporting the diagnosis. Rifabutin, though an effective alternative for antibiotic-resistant <i>H. pylori</i> infections, has been associated with cases of hematologic complications, including neutropenia, as seen in this patient. In 2019, rifabutin was approved for the treatment of <i>H. pylori</i>, and its use is likely to increase. This case, therefore, highlights the importance of early recognition of IDIN as a potential adverse effect of rifabutin treatment, particularly in patients presenting with acute-onset, unexplained fever and hematologic abnormalities. Early detection, discontinuation of the offending agent, and close hematologic monitoring are vital in preventing severe complications of IDIN. Increased awareness among clinicians and further research into the mechanisms of IDIN are necessary to improve patient safety and overall clinical outcomes.