Voriconazole

C. diff Risk

Low

Oral Bioavailability

Excellent

Approximate Cost

IV-$300 PO-$100

Dosing

Renal

Renally cleared, requires dosage adjustment with changes in renal function. Consult a pharmacist for renal dosing.
IV formulation contains sulfobutyl ether beta-cyclodextrin (SBECD) which may accumulate in renal insufficiency.

Other

In pediatric patients <12 years, bioequivalence between the oral tablet and suspension has not been determined; due to possible shortened gastric transit time in infants and children, absorption of tablets may be different than adults

General Information

Common Usage

Aspergillosis

Drug Monitoring

Therapeutic drug monitoring may be helpful to ensure adequate concentrations and exclude toxicity (discuss with ID). Target trough 1-6 mg/L. Collect in heparinized red top tube 0-30 minutes prior to dose and send to Toronto Sick Kids for analysis
Monitor QTc interval in patients at elevated risk
Monitor hepatic profile

Adverse Effects

QTc prolongation
Hepatic enzyme abnormalities
Rash - up to 20%
GI upset
Visual disturbances may occur

Major Interactions

Many via CYP450- suggest review interactions with pharmacist.
Risk when combining with other QTc prolonging agents

Pharmacology

Antimicrobial class: Triazole antifungal, second generation

Route of Elimination: Urine (<2% as unchanged drug)

Average serum half life: Variable and dose dependent.