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Possible clinically significant interaction of itraconazole plus rifampin

J R Todd1, M R Arigala, R L Penn

  • 1Department of Medicine, Section of Infectious Disease, Louisiana State University Medical Center in Shreveport, Shreveport, Louisiana 71130-3932, USA. jtodd@lsuhsc.edu

AIDS Patient Care and Stds
|November 2, 2001
PubMed

Insights

This study observed significant weight loss in two patients taking both itraconazole and rifampin. Weight gain after discontinuing rifampin suggests a potential drug interaction impacting nutrient absorption.

Area of Science:

  • Pharmacology
  • Clinical Medicine
  • Drug Interactions

Background:

  • Itraconazole and rifampin are commonly prescribed antifungal and antibiotic medications, respectively.
  • Concurrent administration of multiple drugs can lead to complex pharmacokinetic and pharmacodynamic interactions.
  • Understanding potential adverse effects is crucial for patient safety and effective treatment.

Observation:

  • Two patients receiving a combination therapy of itraconazole and rifampin for over four months experienced notable weight loss.
  • Patient 1 lost 30 g/day while on the combination therapy, regaining 14 g/day after discontinuing rifampin.
  • Patient 2 lost 41 g/day on the combination therapy, regaining 33 g/day after rifampin cessation.

Findings:

  • Consistent and significant weight loss was observed in both patients during the concurrent use of itraconazole and rifampin.
  • The cessation of rifampin led to a reversal of weight loss, with patients regaining weight.
  • These observations suggest a potential clinically significant drug interaction between itraconazole and rifampin impacting nutritional status.

Implications:

  • The findings highlight a potential adverse drug interaction between itraconazole and rifampin that may affect patient weight and nutritional status.
  • Clinicians should be aware of this potential interaction and monitor patients closely for unexplained weight loss when these drugs are co-administered.
  • Further research is warranted to elucidate the mechanisms underlying this interaction and to establish management guidelines.

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