Voriconazole

Restricted
Restricted

C. diff Risk

Low

Oral Bioavailability

Excellent

Approximate Cost

Spectrum Of Activity

Dosing

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

PO - 400mg PO q12h x 2 doses then 200mg PO q12h

Dose reduction may be required if low body weight

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

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

General Information

Common Usage

Candida infections both mucocutaneous and invasive - i.e. Candidemia

Antifungal prophylaxis in immunocompromised

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+)

Adverse Effects

  • QTc prolongation

  • Hepatotoxicity, renal toxicity

  • Rash; dermatologic reactions

  • Visual disturbance, photophobia, headache, dizziness,

  • ¬†Fluorosis

  • Hypokalemia, hypomagnesemia

Major Interactions

CYP450 interactions ++

Other QTc prolonging agents

Contraindicated with pimozide, quiniDINE, rifampin, carbamazepine, sirolimus, rifabutin, ritonavir, efavirenz, ergot alkaloids, and phenobarbital

Voriconazole may inhibit the metabolism of tacrolimus (need to decrease tacrolimus dose to 1/3 of original dose), cycloSPORINE (need to decrease cycloSPORINE dose by 50%), sulphonylureas, statins, and HIV protease inhibitors other than indinavir

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

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)

Requires ID or Antimicrobial Stewardship approval for onging use without an accepted indication

Pharmacology

Antimicrobial class: Triazole antifungal, second generation

Pregnancy category: D

Average serum half life: Variable

CSF penetration: Therapeutic

Lung penetration: Therapeutic

Urine penetration: Poor