Is Ciprofloxacin in Combination With Beta-lactam Antibiotics a Recipe for Thrombocytosis?: A Case Report of Thrombocytosis in a Patient Receiving Ciprofloxacin and Ceftriaxone.

Thrombocytosis is defined as a platelet count greater than 400,000/mcL. We report the case of a patient who developed thrombocytosis after receiving ciprofloxacin and ceftriaxone therapy. A 73-year-old African-American female presented to the hospital with altered mental status attributed to sepsis and urinary tract infection. Patient was initiated on multiple empiric antibiotic therapy and was subsequently transitioned to ciprofloxacin and ceftriaxone at different times as definitive therapy for treatment of Escherichia coli bacteremia and Escherichia coli urinary tract infection. The patient developed thrombocytosis during and/or proximally to the administration of ciprofloxacin and ceftriaxone. A myeloproliferative source for the thrombocytosis was ruled out by the hematology/oncology team with a negative Janus kinase 2 V617F mutation assay result. In addition, other nondrug reactive sources of thrombocytosis (infection and anemia) were generally ruled out because the thrombocytosis was proximally linked with ciprofloxacin and ceftriaxone administration. The Naranjo Adverse Drug Reaction Probability Scale assigned a score of 5, indicating ciprofloxacin or ceftriaxone independently or in combination as a probable cause of thrombocytosis. This case report suggests that ciprofloxacin in combination with ceftriaxone (a beta-lactam antibiotic) may be a probable cause of thrombocytosis.