Voriconazole

C. diff Risk

Low

Oral Bioavailability

Excellent

Approximate Cost

IV-$300 PO-$100

Spectrum Of Activity

Dosing

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.

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

Average serum half life: Variable and dose dependent.

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