Voriconazole

C. diff Risk

Low

Oral Bioavailability

Excellent

Approximate Cost

IV-$300 PO-$100

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

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

Oral Liquids

Concentration: 40 mg/mL

Not all strengths of oral liquids are listed nor are available on IWK formulary

Tablet/Capsule Strengths

50 mg tablet
200 mg tablet
Tablets and capsules are preferred especially over an unpleasant tasting liquid.
Not all strengths of oral tablets/capsules are listed and they are not all available on the IWK formulary.

Pharmacology

Antimicrobial class: Triazole antifungal, second generation

Average serum half life: Variable and dose dependent.

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