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High-throughput Identification of Synergistic Drug Combinations by the Overlap2 Method
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High-throughput Identification of Synergistic Drug Combinations by the Overlap2 Method

Published on: May 21, 2018

Concomitant use of voriconazole and rifabutin in a patient with multiple infections

Joshua N Schwiesow1, Michael D Iseman, Charles A Peloquin

  • 1Department of Pharmacy, National Jewish Medical and Research Center, 1400 Jackson Street, Denver, CO 80206, USA. SchwiesowJ@njc.org

Pharmacotherapy
|July 29, 2008
PubMed

Insights

Concomitant azole antifungal and rifamycin drug administration is typically contraindicated. This case study demonstrates successful management of coexisting Mycobacterium xenopi and Aspergillus fumigatus infections using rifabutin and therapeutic drug monitoring.

Area of Science:

  • Pulmonology
  • Infectious Diseases
  • Clinical Pharmacology

Background:

  • Concomitant administration of azole antifungals and rifamycins is contraindicated due to drug interactions causing subtherapeutic azole levels.
  • Severe pulmonary disease requires simultaneous treatment for Mycobacterium xenopi and Aspergillus fumigatus infections.

Observation:

  • A 30-year-old woman with severe pulmonary disease caused by M. xenopi and A. fumigatus required concurrent antimycobacterial and antifungal therapy.
  • Rifabutin, a rifamycin with minimal cytochrome P450 (CYP) enzyme induction, was chosen for treatment.
  • Therapeutic drug monitoring (TDM) was implemented to achieve target serum concentrations for all antimicrobial agents.

Findings:

  • Voriconazole dosage frequency was increased from twice daily to three times daily based on TDM to maintain therapeutic levels.
  • The patient experienced a dramatic clinical improvement.
  • She was discharged, remaining free of Aspergillus infection while continuing treatment for her mycobacterial infection.

Implications:

  • Careful drug selection, such as using rifabutin, is crucial when managing combined mycobacterial and fungal infections.
  • Therapeutic drug monitoring of antimicrobial serum concentrations provides a practical model for optimizing treatment efficacy and safety.
  • This approach enables successful management of complex polymicrobial pulmonary infections, improving patient outcomes.

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