Table 4. Effect of Other Drugs on Voriconazole Levels
| Drug/Drug Class | Voriconazole Levels | Recommendations for voriconazole dose adjustments |
|---|---|---|
| Rifampin/Rifabutin (CYP450 Induction) |
Significantly reduced | CONTRAINDICATED |
| Carbamazepine
(Tegretol®) (CYP450 Induction) |
Likely to result in significant reduction | CONTRAINDICATED |
| Long-acting
barbiturates (CYP450 Induction) |
Likely to result in significant reduction | CONTRAINDICATED |
| Phenytoin
(Dilantin®) (CYP450 Induction) |
Significantly reduced | Increase
maintenance dose to 5mg/kg IV Q 12 hrs or 400 mg PO Q 12 hrs (If < 40 kg; 200 mg PO Q 12 hrs) |
| HIV
Protease Inhibitors (PIs) (CYP450 Induction) |
In-vivo studies
showed no effect of indinavir (Crixivan®) on voriconazole; In-vitro studies show potential for interaction |
No dose adjustment
needed with indinavir. Monitor for adverse effects or toxicity when given with other PIs. |
| Non-nucleoside reverse
transcriptase inhibitors (NNRTIs) (CYP450 Induction or Inhibition) |
Potential for inhibition or induction exists | Monitor for adverse effects and toxicity of voriconazole or monitor for clinical efficacy of voriconazole |