Voriconazole: what it does and how to use it safely
Voriconazole is a strong antifungal medicine used for serious fungal infections, like invasive aspergillosis and certain Candida infections. Doctors choose it when infections are severe or when other drugs don’t work. This page gives clear, practical info: what to expect, how to take it, which side effects matter, and common drug interactions to watch for.
How it works and common uses
Voriconazole blocks a fungal enzyme needed to make the cell membrane, which stops fungal growth. You’ll see it used for invasive aspergillosis, serious Candida infections (including some bloodstream infections), and other rare fungal diseases. Treatment is prescription-only and often started in hospital, then continued at home if needed.
Key dosing and administration tips
Oral voriconazole is usually taken twice daily after a loading dose; follow your prescriber's exact plan. Take the tablets on an empty stomach — food can lower how much drug your body absorbs. If you get the IV form, doctors watch kidney function closely because the IV vehicle can build up in people with low kidney function; switching to oral is common for those patients.
Safety, side effects and monitoring
Common short-term effects include visual changes (blurry vision, light sensitivity), nausea, headache, and skin rash. Visual symptoms often appear early and usually go away, but tell your doctor if they’re severe. Voriconazole can hurt the liver — expect liver tests before starting and periodically during treatment. Signs of liver trouble include dark urine, yellowing skin or eyes, nausea, and severe belly pain.
Less common but serious risks: hallucinations or marked mood changes, severe skin reactions, and QT prolongation (a heart rhythm issue). If you notice fainting, chest pain, or severe mental changes, seek medical help right away.
Drug interactions and precautions
Voriconazole interacts with many medicines because it affects the CYP450 enzyme system. It can raise levels of drugs like warfarin, some statins, certain benzodiazepines, and some immunosuppressants. Strong enzyme inducers (for example, rifampin, carbamazepine) can cut voriconazole levels and make it ineffective — these combos are usually avoided. Always tell your prescriber about all medicines, supplements, and herbal products you take.
Pregnancy and breastfeeding: avoid if possible. Voriconazole can harm a developing baby and is generally not recommended in pregnancy. Discuss risks and alternatives with your doctor if you’re pregnant or plan to become pregnant.
Therapeutic drug monitoring (measuring blood levels) is often used for long courses or severe infections to hit an effective but safe range. Labs will also track liver tests regularly. Don’t drive at night or operate heavy machinery until you know how voriconazole affects your vision and alertness.
Bottom line: voriconazole treats serious fungal infections well, but it needs careful monitoring. Follow your prescriber’s instructions, report side effects quickly, and check interactions before adding any new medicine.