Voriconazole

Restricted
C. diff Risk

Low

Oral Bioavailability

Excellent

Dosing

Mild to moderate (Child-Pugh A/B) - Standard loading dose then reduce maintenance by 50%

Severe impairment (Child-Pugh C) - Should only be used if benefit outweighs risk

See drug monitoring information

PO: 400 mg PO q12h x 2 doses, then 200-300 mg PO q12h
May require dose adjustment if low body weight

IV: 6 mg/kg IV q12h x 2 doses, then 4 mg/kg IV q12h

50+ mL/min0 - 50 mL/min400 mg PO q12h x 2 doses, then 200-300 mg PO q12h
May require dose adjustment if low body weightNo dose adjustment

50+ mL/min0 - 50 mL/min6 mg/kg IV q12h x 2 doses, then 4 mg/kg IV q12h6 mg/kg IV q12h x 2 doses, then 4 mg/kg IV q12h
Switch to oral formulation as soon as feasible.
IV voriconazole contains cyclodextrin which can accumulate and cause toxicity.

IV therapy not recommended after first loading dose due to accumulation of cyclodextrin.
Oral dosing does not require modification in renal failure.

6 mg/kg IV q12h x 2 doses, then 4 mg/kg IV q12h

IV therapy not recommended after first loading dose due to accumulation of cyclodextrin.
Oral dosing does not require modification in renal failure.

General Information

Additional Information

Food may decrease oral absorption. Should be taken 1hr before or 1 hr after a meal.

Avoid/limit use of IV formulation in renal failure due to accumulation of vehicle (cyclodextrin).

Adverse Effects

  • QTc prolongation

  • Hepatic enzyme abnormalities

  • Rash - up to 20%

  • Visual disturbance

  • ¬†Fluorosis

  • GI upset

Common Usage

Infectious Diseases consultation recommended for use.

Drug Monitoring

Therapeutic drug monitoring may be helpful to ensure adequate concentrations and exclude toxicity.

QTc interval in patients at elevated risk

Monitor hepatic profile

Creatinine, electrolytes (K+, Mag+, Ca+)

Major Interactions

CYP450 interactions ++

Other QTc prolonging agents

Voriconazole increases concentration of phenytoin. Phenytoin decreases concentration of voriconazole. Drug monitoring recommended.

Recommend review of patient medications due to high frequency of significant interactions.

Pharmacology

Antimicrobial class: Triazole antifungal

Pregnancy category: D