antibioticsbooks

194 PART 4 Antifungal Drugs
Adverse Reactions
Posaconazole seems to be well tolerated, though it
can cause hepatotoxicity, nausea, and rash. It has
the same propensity to cause drug interactions via
cytochrome P450 as the other azoles. We will learn
more about the adverse effect spectrum of posaconazole
as clinical experience with it grows.
Dosing Issues
Posaconazole is available only as an oral suspension.
It should always be administered with food
to increase its absorption; foods with a high fat
concentration, nutritional supplements containing
fat, and low-pH beverages like soda all increase
absorption.
■ ■ Important Facts
• Posaconazole’s primary use is in the prophylaxis
of fungal infections in high-risk patients.
As with voriconazole, many of these patients
are taking immunosuppressants that interact
with posaconazole, so keep close tabs on those
drug concentrations.
• Clinical data with posaconazole for Zygomycete
infections are growing, and posaconazole is
emerging as a drug of choice for these infections.
Some clinicians prefer to start with an
amphotericin B formulation to avoid the unpredictable
pharmacokinetics of posaconazole,
then transition as patients improve.
• Posaconazole has issues with absorption. Highfat
meals and acidic beverages boost absorption
substantially and may be required for adequate
absorption in some patients. Proton-pump