[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Azole antifungals](https://durgical.com/en/pharmacology/classes/azole-antifungals/) › Voriconazole

[Pharmacology](https://durgical.com/en/pharmacology/) · [Azole antifungals](https://durgical.com/en/pharmacology/classes/azole-antifungals/)

# Voriconazole

Triazole of choice for invasive aspergillosis, by mouth or vein. It causes visual changes and sun sensitivity, and its levels vary with CYP2C19 genes.

Updated 2026-11-01

- Class: [Azole antifungals](https://durgical.com/en/pharmacology/classes/azole-antifungals/)
- Enzyme: Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme)
- ATC code: J02AC03
- WHO Model List of Essential Medicines

✂**Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme)**Voriconazole

ⓘ The figure shows voriconazole bound to CYP51 from the yeast Saccharomyces cerevisiae, a model of the fungal enzyme.

**Target in 3D:** Lanosterol 14α-demethylase (CYP51, the fungal ERG11 enzyme). PDB structure 5HS1 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/5HS1) · Drag to rotate · pinch to zoom

## Mechanism of action

Voriconazole inhibits the fungal cytochrome P450-mediated 14α-demethylation of lanosterol, an essential step of ergosterol synthesis. 14α-methyl sterols accumulate and ergosterol is lost, which stops the fungus. Its spectrum includes Aspergillus, Candida, Scedosporium and Fusarium. It is metabolised by CYP2C19, CYP2C9 and CYP3A4 and inhibits them, so interactions are many.

- Voriconazole blocks fungal CYP51
- Ergosterol is lost and methyl sterols build up
- Aspergillus hyphae stop growing

## Pharmacokinetics

**Absorption**
Good oral absorption; tablets are given at least an hour away from meals.

**Metabolism**
Liver, mainly by CYP2C19, which is genetically polymorphic (poor metabolisers have higher levels); saturable, non-linear kinetics with high variability between patients.

**Elimination**
As metabolites; the intravenous vehicle (a cyclodextrin, SBECD) accumulates in moderate or severe kidney impairment.

**Half-life**
Dose-dependent, so it does not predict accumulation.

## Indications

- Invasive aspergillosis (first-line). [Aspergillosis →](https://durgical.com/en/conditions/aspergillosis/)
- Candidaemia in non-neutropenic patients and other deep Candida infections. [Candidiasis: oral, oesophageal and invasive →](https://durgical.com/en/conditions/candidiasis-oral-oesophageal-and-invasive/)
- Oesophageal candidiasis. [Infectious and pill-induced oesophagitis (Candida, HSV, CMV) →](https://durgical.com/en/conditions/infectious-and-pill-induced-oesophagitis/)
- Serious infections by Scedosporium and Fusarium in patients intolerant of or refractory to other therapy.

## Adverse effects

### Common

- Visual disturbances: blurred or altered vision, photophobia, altered colour vision
- Transient visual or auditory hallucinations
- Fever, nausea, vomiting, headache
- Rash and photosensitivity
- Raised liver tests; tachycardia

### Serious (rare, important)

- Hepatotoxicity, including hepatitis and fulminant liver failure
- QT prolongation, torsade de pointes, cardiac arrest
- Severe skin reactions (SJS, TEN, DRESS); phototoxicity and squamous cell skin cancer with long use
- Optic neuritis and papilloedema with long treatment
- Acute kidney failure, adrenal insufficiency, pancreatitis, fluorosis and periostitis

## Contraindications

- Hypersensitivity to voriconazole
- CYP3A4 substrates with serious toxicity: sirolimus, pimozide, quinidine, ergot alkaloids, rifabutin, among others
- Strong inducers that make it fail: rifampicin, carbamazepine, long-acting barbiturates, St John's wort, high-dose ritonavir and efavirenz

## Key interactions

**Sirolimus**
Contraindicated: sirolimus levels rise sharply.

**Tacrolimus and cyclosporine**
Levels rise; their dose is reduced at the start and blood levels are checked often.

**Rifampicin and carbamazepine**
Contraindicated: voriconazole levels fall and treatment fails.

**Warfarin and other coumarins**
Prothrombin time rises; INR is monitored.

**Phenytoin**
Two-way interaction: phenytoin lowers voriconazole and voriconazole raises phenytoin; doses are adjusted.

## What is monitored

- Liver tests and bilirubin at the start, then weekly during the first month
- Potassium, magnesium and calcium before and during treatment; creatinine
- Visual acuity, visual field and colour vision if treatment lasts more than 28 days
- Blood levels (therapeutic drug monitoring), given the large variability
- Skin examination during long treatment

## Administration and safety

- Intravenous: slow infusion only, never as a bolus.
- Do not infuse at the same time as blood products or short infusions of concentrated electrolytes, even through separate lines.
- Correct low potassium, magnesium and calcium before starting.
- In moderate or severe kidney impairment the oral route is preferred, because the intravenous vehicle accumulates.
- Oral tablets: at least one hour before or after a meal.

## Nursing care

- Warn that blurred vision or light sensitivity are common; patients should not drive at night during treatment.
- Teach strict sun protection (clothing, high-SPF sunscreen), especially in children.
- Report hallucinations, palpitations or fainting.
- Watch for signs of liver injury and for symptoms of adrenal insufficiency or Cushing syndrome when corticosteroids are also used.
- Women who can become pregnant need effective contraception.

## Pregnancy and breastfeeding

Can cause fetal harm (malformations in animals); effective contraception is advised during treatment.

## Memory aid

«VORI = VIEW»: seeing lights and colours, hallucinations and sunburn, while it clears Aspergillus.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the first-line drug for invasive aspergillosis in most guidelines?

Voriconazole (isavuconazole is an alternative; amphotericin B for intolerance or resistance).

## Why are voriconazole blood levels so variable?

It is cleared mainly by CYP2C19, which is genetically polymorphic, and its metabolism saturates, giving non-linear kinetics.

## A patient on voriconazole describes flashes of light and brighter colours. What is it?

The common visual adverse effect of voriconazole; it is usually transient, but vision is checked if treatment is long.

## Why is oral voriconazole preferred in moderate kidney impairment?

The intravenous vehicle, a cyclodextrin (SBECD), accumulates when the kidneys fail.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/voriconazole/)

## Related drugs

- [Posaconazole](https://durgical.com/en/pharmacology/posaconazole/)
- [Isavuconazole](https://durgical.com/en/pharmacology/isavuconazole/)
- [Fluconazole](https://durgical.com/en/pharmacology/fluconazole/)
- [Amphotericin B](https://durgical.com/en/pharmacology/amphotericin-b/)

## Related conditions

- [Aspergillosis](https://durgical.com/en/conditions/aspergillosis/)
- [Candidiasis: oral, oesophageal and invasive](https://durgical.com/en/conditions/candidiasis-oral-oesophageal-and-invasive/)
- [Infectious and pill-induced oesophagitis (Candida, HSV, CMV)](https://durgical.com/en/conditions/infectious-and-pill-induced-oesophagitis/)

[← Back to the class: Azole antifungals](https://durgical.com/en/pharmacology/classes/azole-antifungals/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - VORICONAZOLE tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4fe672ff-2cef-4f88-ab85-5a4b586da20d) (DailyMed (U.S. National Library of Medicine), 2026); [DailyMed - VORICONAZOLE injection, powder, lyophilized, for solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=d962d459-254f-4b78-ae28-7d9ec5d4e4d5) (DailyMed (U.S. National Library of Medicine), 2026); [Voriconazole: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a605022.html) (MedlinePlus (U.S. National Library of Medicine), 2022); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 61 (McGraw Hill, 2023).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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