What is voriconazole used for?

October 7, 2025 •

4 min read

Annually, invasive fungal infections have an estimated global incidence of 6.5 million, with a directly attributable mortality rate of around 68%. For many of these severe cases, a key question for clinicians is: what is voriconazole used for in battling these life-threatening conditions?

Quick Summary

Voriconazole is a broad-spectrum triazole antifungal medication prescribed for serious, often life-threatening, fungal infections such as invasive aspergillosis, candidemia, and esophageal candidiasis.

Key Points

Primary Use: Voriconazole is a triazole antifungal used to treat serious fungal infections, most notably invasive aspergillosis.
Mechanism: It works by inhibiting the synthesis of ergosterol, an essential component of the fungal cell membrane, thereby stopping fungal growth.
Spectrum of Activity: It is effective against a broad range of fungi, including Aspergillus species, Candida species (including some fluconazole-resistant strains), Scedosporium, and Fusarium.
Administration: Voriconazole is available in both intravenous (IV) and oral forms (tablets and liquid), allowing for a switch from hospital to home-based care.
Common Side Effects: Common side effects include temporary visual disturbances (blurred vision, color changes), skin rashes, and elevated liver enzymes.
Serious Risks: Serious risks include severe liver injury, heart rhythm problems (QT prolongation), and increased sensitivity to sunlight (photosensitivity) that can raise skin cancer risk with long-term use.
Patient Monitoring: Due to its side effects and drug interactions, patients require regular monitoring of liver function, electrolytes, and vision.

Introduction to Voriconazole (Vfend)

Voriconazole, sold under the brand name Vfend among others, is a powerful second-generation triazole antifungal medication. It is a critical tool for treating invasive and serious fungal infections, particularly in patients who are immunocompromised. Unlike some earlier antifungals, voriconazole has a broad spectrum of activity against a wide range of yeasts and molds. It can be administered both intravenously (IV) in a hospital setting and orally as tablets or a liquid suspension, which allows for flexibility in treatment plans.

How Does Voriconazole Work?

The mechanism of action for voriconazole involves disrupting the integrity of the fungal cell membrane. Like other azole antifungals, it works by inhibiting a fungal-specific enzyme, lanosterol 14-alpha-demethylase. This enzyme is crucial for the synthesis of ergosterol, an essential component of the fungal cell membrane. By blocking ergosterol production, voriconazole causes the accumulation of abnormal sterols, leading to a damaged and dysfunctional cell wall, which ultimately stops the growth of the fungus. This action is generally considered fungistatic (inhibiting growth) against Candida species but can be fungicidal (killing the fungus) against Aspergillus species.

Primary Uses of Voriconazole

Voriconazole is prescribed by doctors for a range of serious fungal infections. It is often considered a first-line treatment for some of the most dangerous invasive mold infections.

Key Indications:

Invasive Aspergillosis: Voriconazole is a primary therapy for invasive aspergillosis, a severe infection that typically starts in the lungs and can spread to other organs, especially in immunocompromised individuals. Clinical trials have shown it to have superior response rates and survival benefits compared to older treatments like amphotericin B for this condition.
Candidemia and Disseminated Candidiasis: It is used for candidemia (fungal infection in the blood) in non-neutropenic patients and for other deep tissue Candida infections, including those affecting the abdomen, kidneys, bladder wall, and wounds. It is also effective against some fluconazole-resistant Candida species like C. krusei.
Esophageal Candidiasis: Voriconazole is used to treat esophageal candidiasis, a yeast infection that can cause white patches in the throat and mouth. Studies have found it to be at least as effective as fluconazole for this use.
Scedosporiosis and Fusariosis: For patients who are intolerant of or have infections refractory to other antifungal treatments, voriconazole is an important option for treating serious infections caused by Scedosporium apiospermum and Fusarium species.

Administration

Voriconazole is typically administered based on a prescribed schedule determined by a healthcare professional. The initial administration may involve a higher amount to quickly reach necessary levels in the body, followed by regular amounts given periodically. Administration is often initiated intravenously (IV) in a hospital setting. Once a patient's condition stabilizes and they can take oral medication, a healthcare provider may transition them to oral forms like tablets or suspension. Oral voriconazole should be taken on an empty stomach to ensure proper absorption. The overall length of treatment is tailored to the specific infection and the patient's individual response.

Potential Side Effects and Monitoring

While effective, voriconazole has a number of potential side effects that require careful monitoring by a healthcare provider.

Common Side Effects

Visual Disturbances: This is one of the most common side effects, affecting up to 28% of patients. It can include blurred vision, changes in color vision, and sensitivity to light (photophobia). Patients are often advised not to drive at night.
Skin Reactions: Rashes are common, and the drug significantly increases skin sensitivity to the sun (photosensitivity). Use of sunscreen and protective clothing is crucial.
Elevated Liver Enzymes: Voriconazole is metabolized by the liver and can cause liver function test abnormalities.
Gastrointestinal Issues: Nausea, vomiting, and diarrhea are also frequently reported.

Serious Side Effects

Hepatotoxicity (Liver Injury): Severe liver injury, though less common, can occur. Regular blood tests to monitor liver function are essential during treatment.
QT Prolongation: The medication can affect heart rhythm, a condition known as QT prolongation, which can be life-threatening. This risk is higher for patients with pre-existing heart conditions or electrolyte imbalances.
Severe Skin Reactions: Rarely, life-threatening skin reactions like Stevens-Johnson syndrome (SJS) can occur.
Neurological Effects: Hallucinations, confusion, and dizziness have been reported.
Long-term Effects: Long-term use has been associated with bone pain (periostitis) and an increased risk of skin cancer (squamous cell carcinoma), especially in transplant patients.

Comparison with Other Antifungals

Voriconazole holds a distinct place among antifungal agents.


Feature	Voriconazole	Fluconazole	Amphotericin B
Primary Spectrum	Aspergillus, Candida (including some resistant strains), Scedosporium, Fusarium	Mainly Candida and Cryptococcus	Very broad spectrum, but with significant toxicity
Key Advantage	First-line therapy for invasive aspergillosis; good oral bioavailability	Good safety profile; excellent for common Candida infections	Effective against a wide range of fungi, including Zygomycetes
Major Drawback	Vision changes, photosensitivity, many drug interactions	Limited activity against molds like Aspergillus	High risk of kidney toxicity (nephrotoxicity) and infusion-related reactions

Compared to other azoles like fluconazole and itraconazole, voriconazole has a broader spectrum, particularly against molds. While itraconazole also covers Aspergillus, voriconazole often shows greater potency and has better bioavailability that isn't dependent on an acidic stomach environment. Isavuconazole is a newer azole with a similar spectrum to voriconazole but may have a lower rate of vision and cardiac side effects.

Conclusion

So, what is voriconazole used for? It is an indispensable medication for combating some of the most severe and invasive fungal infections known, especially invasive aspergillosis. Its development marked a significant advancement over older therapies like amphotericin B, offering better efficacy and survival rates for this deadly infection. However, its use requires careful management and monitoring by healthcare professionals due to a distinct side effect profile and a high potential for drug interactions. For patients with life-threatening fungal diseases, voriconazole remains a cornerstone of modern antifungal therapy.

For more information on the clinical efficacy and safety of voriconazole, you can refer to authoritative sources such as this detailed review from the National Institutes of Health: Voriconazole: the newest triazole antifungal agent

Frequently Asked Questions

The most common side effect is temporary and reversible visual disturbances, including blurred vision, altered color perception, and increased sensitivity to light.

No, oral voriconazole should be taken on an empty stomach, at least one hour before or one hour after a meal. Food, especially high-fat meals, can decrease its absorption.

Voriconazole is a strong antifungal agent, not an antibiotic. Antibiotics are used to treat bacterial infections, while antifungals like voriconazole are used to treat infections caused by fungi.

Voriconazole is considered a first-line, or primary, therapy for invasive aspergillosis, a life-threatening mold infection, particularly in immunocompromised patients.

The duration of treatment depends on the type and severity of the fungal infection as well as the patient's response and immune status. A healthcare professional will determine the appropriate length of treatment.

Voriconazole can cause photosensitivity, making the skin much more sensitive to sunlight and UV light. Patients are advised to avoid prolonged sun exposure and use high-SPF sunscreen and protective clothing to prevent severe sunburns and reduce the long-term risk of skin cancer.

Yes, regular blood tests are necessary while taking voriconazole. Doctors will monitor blood levels of the drug itself (therapeutic drug monitoring), as well as check liver function, kidney function, and electrolyte levels (like potassium and magnesium) to manage side effects.