antibioticsbooks

190 PART 4 Antifungal Drugs
Moderate: Candida glabrata (can be susceptible
dose-dependent, or resistant), Candida albicans
that are fluconazole-resistant, Fusarium species
Poor: Zygomycetes
Adverse Effects
In addition to the hepatotoxicity, rash, and drug
interactions that are common with this class, voriconazole
has some agent-specific adverse effects
worth watching.
Renal: The cyclodextrin solubilizer that intravenous
voriconazole comes in is known to accumulate
in renal dysfunction. This vehicle is
thought to be nephrotoxic, but it is almost certainly
less nephrotoxic that amphotericin B, so
the use of intravenous voriconazole with renally
insufficient patients is a risk/reward equation
that should be considered with each patient.
Visual effects: Visual effects such as seeing wavy
lines or flashing are very common and doserelated;
they tend to go away with continued
use. Visual hallucinations can also occur but
are less common.
Dosing Issues
Voriconazole has highly variable interpatient pharmacokinetics
and nonlinear elimination, making it
difficult to dose correctly. Some centers monitor voriconazole
trough concentrations, but tests are not yet
widely available. If you are committing your patient
to an extended course of therapy for voriconazole,
consider checking a trough. Also consider trough
concentrations for any patient who is not responding
to therapy or experiencing continual adverse effects.