Voriconazole is an antifungal medicine used to treat serious, invasive fungal infections, most notably invasive aspergillosis. It belongs to a class of medicines called triazole antifungals, and is considered a first-line treatment for aspergillosis by major treatment guidelines. It is a prescription-only medicine, available in both oral and intravenous forms.

• Therapeutic Class: Systemic antifungal medicine.

• Pharmacological Class: Triazole antifungal (ergosterol synthesis inhibitor).

• Drug Family: Broad-spectrum azole antifungals.

• ATC Classification: J02AC03 (Voriconazole).

Approved: Invasive aspergillosis; serious fungal infections caused by Fusarium species and Scedosporium apiospermum in patients intolerant of or refractory to other therapy; candidemia in non-neutropenic patients and certain other deep tissue Candida infections; and esophageal candidiasis.

Commonly used for: Immunocompromised patients — such as those with blood cancers, or stem cell/organ transplant recipients — who develop invasive aspergillosis or other serious fungal infections.

Off-label use (only under medical guidance): Sometimes used as antifungal prophylaxis in high-risk patients, or for other resistant fungal infections, under specialist guidance.

• Oral tablets: 50 mg and 200 mg.

• Oral suspension: 200 mg/5 mL (40 mg/mL).

• Injection (intravenous, lyophilized powder for reconstitution): 200 mg per vial.

Voriconazole blocks an enzyme fungi need to produce ergosterol, an essential component of the fungal cell membrane. Without adequate ergosterol, the fungal cell membrane becomes unstable and leaky, which stops the fungus from growing and helps the body clear the infection.

Standard loading dose (invasive aspergillosis, IV): 6 mg/kg intravenously every 12 hours for the first 24 hours (two doses).

Standard maintenance dose (IV): 4 mg/kg intravenously every 12 hours, continued for at least 7 days, then switched to oral therapy once the patient can tolerate it and has improved clinically.

Standard oral dosing: A loading dose of 400 mg orally every 12 hours on Day 1 (300 mg every 12 hours for patients under 40 kg), followed by a maintenance dose of 200 mg orally every 12 hours (150 mg every 12 hours for patients under 40 kg), increased to 300 mg (or 200 mg for lower weight) every 12 hours if response is inadequate.

Route: Intravenous infusion or oral tablets/suspension; oral doses should generally be taken 1 hour before or 1 hour after a meal.

Missed dose: Take as soon as remembered; contact the treating team for guidance if a dose is significantly delayed, given the seriousness of the infections treated.

Overdose: May worsen known side effects such as visual disturbances, liver enzyme changes, or QT prolongation; requires medical attention.

• Common: Visual disturbances (blurred vision, altered colour perception, light sensitivity — often temporary and dose-related), fever, rash, nausea, vomiting, and elevated liver enzymes.

• Serious: Liver toxicity (including rare severe hepatic reactions), QT interval prolongation, severe skin reactions (Stevens-Johnson syndrome and related conditions), and, with long-term use, skin cancer risk (particularly squamous cell carcinoma) and periostitis (bone pain from fluoride accumulation).

• Emergency symptoms: Yellowing of the skin/eyes, severe skin rash with blistering, a very slow or irregular heartbeat, or sudden vision loss.

• Recovery advice: Visual disturbances are common, usually mild, and typically resolve as treatment continues or after stopping; patients are generally advised to avoid driving at night or in situations requiring sharp vision if these effects occur, and to use sun protection given the long-term skin cancer risk with prolonged therapy.

• Pregnancy: Not recommended; may cause fetal harm.

• Breastfeeding: Not recommended during treatment.

• Liver disease: Requires dose adjustment (typically halving the maintenance dose) in mild to moderate impairment; used with caution and closer monitoring in severe impairment, given increased hepatotoxicity and drug accumulation risk.

• Kidney disease: The IV formulation contains an excipient that can accumulate in significant renal impairment; oral dosing is generally preferred in this situation, though oral dosing itself needs no adjustment for kidney function alone.

• Elderly: Used with routine monitoring; no specific dose adjustment based on age alone, though overall risk factors are reviewed.

• Children: Used in pediatric patients under specialist guidance, with weight-based dosing that differs from adult dosing.

• Pimozide, quinidine, and certain other QT-prolonging drugs: contraindicated in combination with voriconazole due to serious cardiac risk.

• Rifampin, rifabutin, carbamazepine, long-acting barbiturates, and St. John's Wort: significantly reduce voriconazole levels; generally contraindicated or requires specific dose adjustment guidance.

• Sirolimus: contraindicated, as voriconazole significantly increases sirolimus levels.

• Numerous CYP2C9, CYP2C19, and CYP3A4 substrate drugs (e.g., certain statins, warfarin, cyclosporine, tacrolimus, certain benzodiazepines): voriconazole can significantly increase their levels, often requiring dose reduction and closer monitoring — a full medicine review is essential before starting.

• Invasive Fungal Infection Treatments

• Triazole Antifungals

• Immunocompromised Patient Supportive Care

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• https://www.pfizermedical.com/vfend

• https://www.sciencedirect.com/science/article/abs/pii/S1156523325000186

The information on this page is for educational purposes only and is not a substitute for medical advice. Please consult your doctor to know if this treatment is appropriate for your condition.