Antimicrobials
Voriconazole

Voriconazole

Low
Excellent
Non-formulary.

Spectrum of Activity

Dosing

General Information

Non-formulary at MSH.

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

Antifungal prophylaxis in immunocompromised patients.

Rationale for monitoring voriconazole levels:

  • Efficacy: subtherapeutic level may be associated with poor clinical response to therapy.
  • Safety: high levels may be associated with adverse effects such as hepatotoxicity and neurotoxicity. Levels may also be required if voriconazole is taken concomitantly with other drugs that interact.

Accepted therapeutic trough range: 1-5 mg/L

How to order levels: 

  • Orders for routine trough level: processed off-site Dynacare (turnaround time up to 6 days)
  • Orders for stat trough level: processed off-site Sick Kids (turnaround time 24-48 hrs).

Other suggested monitoring:

  • QTc interval in patients at elevated risk.
  • Monitor hepatic profile.
  • Infusion related effects: tachycardia, dyspnea, fever, flushing.
  • QTc prolongation
  • Hepatic enzyme abnormalities
  • Rash - up to 20%
  • Visual disturbance
  • Fluorosis
  •  GI upset

CYP450 interactions ++.

Other QTc prolonging agents.

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

Antimicrobial class: Triazole antifungal, Second generation

Pregnancy category: D

Average serum half life: Variable, dose-dependent. Steady-state is achieved by day 3 when an IV loading dose is administered and between days 5 and 8 if no loading dose is used (Purkins 2003).

CSF penetration: Therapeutic

Lung penetration: Therapeutic

Urine penetration: Poor