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Palliative cancer care - oral problems - Management
What drug interactions can occur with fluconazole?

Significant drug interactions with fluconazole include:

  • Warfarin:
    • On the basis of kinetic studies, it has been determined that an approximately 20% reduction in the warfarin dose may be needed when using fluconazole 50 mg daily, although this can vary considerably between people [Baxter, 2006].
    • Consequently, prothrombin times should be closely monitored and the anticoagulant dosage reduced as necessary [Baxter, 2006].
  • Sulphonylureas:
    • The increased plasma concentration of sulphonylureas in people receiving this combination requires monitoring for possible hypoglycaemic episodes.
    • However, there are only case reports of fluconazole causing episodes of hypoglycaemia in people taking glipizide or glibenclamide [Baxter, 2006].
  • Interactions with antineoplastics, antivirals, and immunosuppressants:
    • Antineoplastics. Preliminary evidence suggests that the pharmacokinetics of fluconazole are less likely than itraconazole to be affected by antineoplastics. Fluconazole may be the antifungal drug of choice in people receiving chemotherapy [Baxter, 2006].
    • Antiviral drugs. There are few clinically significant drug interactions with fluconazole.
    • Immunosuppressants:
      • Serum levels of tacrolimus given orally may be considerably increased by oral fluconazole, and tacrolimus dose reductions may be needed.
      • Increased plasma concentration of ciclosporin has been observed. Monitor for possible toxicity and dose adjustment.

[Baxter, 2006; BNF 52, 2006]

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