Table 5. Effect of Voriconazole on Levels of Other Drugs
| Drug/Drug Class |
Drug
Level
|
Drug
Dosage Adjustment
|
|
Sirolimus
(Rapamune®)
(CYP3A4 Inhibition) |
Significantly
increased
|
CONTRAINDICATED
|
|
Terfenadine,
astemizole, cisapride, pimozide, quinidine
(CYP450 Inhibition) |
Drug
levels likely increased
|
CONTRAINDICATED
|
|
Ergot
alkaloids
(CYP450 Inhibition) |
Drug
levels likely increased
|
CONTRAINDICATED
|
|
Cyclosporine
(CYP3A4 Inhibition) |
AUC
significantly increased
|
Decrease
cyclosporine dose by one-half and follow levels
|
|
Tacrolimus
(Prograf®)
(CYP3A4 Inhibition) |
Significantly
increased
|
Decrease
tacrolimus dose by one-third and follow levels
|
|
Phenytoin (Dilantin®) |
Significantly
increased
|
Frequently
monitor phenytoin levels and monitor for adverse effects
|
| Warfarin
(Coumadin®) (CYP2C9 Inhibition) |
Increased
INR/PT
|
Monitor
INR/PT; may require dose adjustment of warfarin
|
| Omeprazole
(Prilosec®) (CYP2C19/3A4 Inhibition) |
Significantly
increased
|
If
omeprazole dose > 40 mg/day decrease dose by one-half; other
PPIs may require dose adjustment
|
|
HIV Protease Inhibitors
(PIs) |
No
effects on indinavir;
|
Monitor
for adverse effects and toxicity of PIs
|
| Non-nucleoside reverse transcriptase inhibitors (NNRTIs) (CYP3A4 Inhibition) |
Potential
for increased levels
|
Monitor
for adverse effects and toxicity of NNRTIs
|
| HMG-CoA
Reductase Inhibitors (CYP3A4 Inhibition) |
Potential
for increased levels
|
Monitor
for adverse effects; may require dose adjustment of the HMG - CoA Reductase
Inhibitor
|
| Dihydropyridine
calcium channel blockers (CCBs) (CYP2C9 Inhibition) |
Potential
for increased levels
|
Monitor
for adverse effects; may require dose adjustment of CCB
|
| Sulfonylurea (CYP2C9 Inhibition) |
Potential
for increased levels
|
Monitor
for hypoglycemia; may require dose adjustment
|
| Vinka
alkaloids (CYP3A4 Inhibition) |
Potential
for increased levels
|
Monitor
for adverse events and neurotoxicity; may require dose adjustment of vinka
alkaloids
|
| Cyclophosphamide (CYP3A4 Inhibition) |
May
prevent conversion to active metabolite
|
Unknown
|
AUC = area-under-the-curve; INR = international normalized ratio; PT = prothrombin time; PPI = proton pump inhibitor
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