Ceftriaxone-Induced Leukopenia During Inpatient Rehabilitation: A Case Report.

Ceftriaxone is a commonly used third-generation cephalosporin with a favorable safety profile and widespread use across acute and post-acute care settings. Although rare, hematologic adverse effects such as leukopenia and neutropenia have been reported. These complications may be underrecognized in inpatient rehabilitation populations, where patients frequently have multiple comorbidities and ongoing antimicrobial exposure. An 80-year-old man undergoing inpatient rehabilitation for critical illness myopathy developed progressive leukopenia following initiation of ceftriaxone for a suspected urinary tract infection. Baseline laboratory studies demonstrated anemia and thrombocytopenia with a normal white blood cell (WBC) count. After ceftriaxone initiation, the WBC count declined to a nadir of 2.73 ×10³/µL with an absolute neutrophil count (ANC) of 1.45 ×10³/µL. The patient remained clinically stable without infectious complications. The temporal relationship between ceftriaxone exposure and leukopenia, improvement following drug discontinuation, and absence of alternative etiologies support a diagnosis of probable ceftriaxone-induced leukopenia. Beta-lactam-associated leukopenia is typically idiosyncratic, reversible, and more likely to occur in older adults and patients with comorbid illness. In rehabilitation settings, unrecognized cytopenias may disrupt therapy participation and delay discharge planning. Ceftriaxone-induced leukopenia is an uncommon but clinically significant adverse effect that may occur even during short courses of therapy. Routine laboratory monitoring and early recognition are essential in inpatient rehabilitation settings to prevent complications and ensure continuity of functional recovery.