antibioticsbooks

182 PART 4 Antifungal Drugs
Adverse Effects
Though fluconazole is generally well tolerated, it
can cause hepatotoxicity or rash. It has a lower
propensity for serious drug interaction than many
other azoles, but interactions still occur with many
drugs metabolized by the cytochrome P450 system.
QTc prolongation is also possible.
Dosing Issues
Fluconazole doses for systemic fungal infections
have been escalated, particularly for the treatment
of Candida glabrata infections. Be sure to adjust
dosing with regard to renal function, because the
drug is eliminated through the urine. Vulvovaginal
candidiasis requires only a one-time dose of 150 mg
of fluconazole.
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Important Facts
• Fluconazole is poorly active against all
Candida krusei and some Candida glabrata.
If you are using it for the latter infection, it is
best to check susceptibilities and give 800 mg
per day of fluconazole after a loading dose. If
your lab does not do susceptibility testing of
fungi, consider an alternative agent such as an
echinocandin.
• Fluconazole is often given as prophylaxis
against Candida infections in susceptible
populations like intensive care unit patients
or patients with some cancers. Are you treating
a patient who was receiving it and now
has yeast in the blood? Try an echinocandin
instead.