[Immune thrombocytopenia attributed to norfloxacin]

Area of Science:

• Pharmacology
• Hematology
• Immunology

Background:

• Urinary tract infections are commonly treated with antibiotics like norfloxacin.
• Thrombocytopenia, characterized by low platelet counts, can arise from various causes, including medication side effects.

Observation:

• A 65-year-old woman presented with hemorrhagic diathesis and severe thrombocytopenia (1 x 10(9)/l) within a week of completing a norfloxacin course for cystitis.
• Bone marrow examination revealed increased megakaryopoiesis, suggesting heightened platelet production.

Findings:

• Norfloxacin-induced immune thrombocytopenia was diagnosed in the absence of other causative factors.
• No specific norfloxacin-dependent antibodies against platelets were identified.
• Treatment with prednisone (1.5 mg/kg/day) led to platelet count normalization within 5 days.

Implications:

• This case highlights the potential for norfloxacin to induce immune-mediated thrombocytopenia.
• Early diagnosis and corticosteroid therapy are crucial for managing this adverse drug event.
• Awareness of this side effect is important for clinicians prescribing fluoroquinolones.