Probable fidaxomicin-induced pancytopenia

Area of Science:

• Pharmacology
• Hematology
• Infectious Diseases

Background:

• Clostridium difficile infection (CDI) is a significant healthcare-associated infection.
• Recurrent CDI poses treatment challenges and may require multiple therapeutic approaches.
• Fidaxomicin is an antibiotic used for CDI treatment, but its adverse effects require monitoring.

Observation:

• A 33-year-old female with recurrent CDI presented with pancytopenia during fidaxomicin therapy.
• Hematologic parameters including platelet count, hemoglobin, and white blood cell count progressively declined after initiating fidaxomicin.
• Despite filgrastim administration, hematologic values continued to decrease, indicating a potential link to fidaxomicin.

Findings:

• The patient's pancytopenia resolved within three days of fidaxomicin discontinuation.
• The Naranjo adverse drug reaction probability scale indicated a probable association between fidaxomicin and the observed pancytopenia (score of 6).

Implications:

• This case highlights a potential adverse drug reaction of fidaxomicin, specifically pancytopenia.
• Clinicians should monitor complete blood counts in patients receiving fidaxomicin, especially those with a history of hematologic abnormalities.
• Further investigation may be warranted to elucidate the mechanism of fidaxomicin-induced hematotoxicity.