Is Vfend affected by genetics?

Yes — the active ingredient is metabolized by a gene known to vary between individuals.

Relevant genes: CYP2C19

Vfend is affected by pharmacogenetics through the CYP2C19 gene. Your genotype for this gene can change how your body processes Vfend, which can affect both how well it works and how well you tolerate it. The strongest evidence level on this page is Strong, based on CPIC or FDA guidelines.

What's in Vfend

voriconazole affected by CYP2C19

Affected by CYP2C19 · CPIC, FDA · Strong evidence

Read the full voriconazole genetics guide →

Voriconazole phenotype recommendations

Published guidance from CPIC and FDA on how voriconazole should be dosed or substituted based on your CYP2C19 phenotype.

Phenotype	What it means	Recommendation	Evidence
Ultrarapid Metabolizer CYP2C19	Your body breaks down voriconazole much faster than normal, which means the drug is unlikely to reach effective levels to fight your infection. Your doctor should choose a different antifungal medication.	CPIC Choose an alternative agent that is not dependent on CYP2C19 metabolism as primary therapy in lieu of voriconazole. Such agents include isavuconazole, liposomal amphotericin B, and posaconazole. FDA Initiate therapy with recommended starting dose.	Strong
Rapid Metabolizer CYP2C19	Your body breaks down voriconazole faster than normal, which may prevent the drug from reaching effective levels. Your doctor should consider a different antifungal medication.	CPIC Choose an alternative agent that is not dependent on CYP2C19 metabolism as primary therapy in lieu of voriconazole. Such agents include isavuconazole, liposomal amphotericin B, and posaconazole. FDA Initiate therapy with recommended starting dose.	Strong
Normal Metabolizer CYP2C19	Your body processes voriconazole at a normal rate, so this antifungal medication should work as expected at the standard dose.	CPIC Initiate therapy with recommended standard of care dosing. FDA Initiate therapy with recommended starting dose.	Strong
Intermediate Metabolizer CYP2C19	Your body breaks down voriconazole slightly more slowly than normal, leading to somewhat higher drug levels. The standard dose is still recommended, but your doctor may monitor your levels.	CPIC Initiate therapy with recommended standard of care dosing. FDA Monitor drug levels closely and consider dose adjustment due to higher systemic concentrations.	Moderate
Poor Metabolizer CYP2C19	Your body breaks down voriconazole very slowly, causing the drug to build up to high levels that increase the risk of side effects. A different antifungal medication is recommended, or a lower dose with close monitoring.	CPIC Choose an alternative agent that is not dependent on CYP2C19 metabolism as primary therapy in lieu of voriconazole. Such agents include isavuconazole, liposomal amphotericin B, and posaconazole. In the event that voriconazole is considered to be the most appropriate agent, based on clinical advice, for a patient with poor metabolizer genotype, voriconazole should be administered at a preferably lower than standard dosage with careful therapeutic drug monitoring. FDA Monitor drug levels closely and reduce dose. Consider alternative antifungal therapy if adverse reactions occur.	Strong
Likely Intermediate Metabolizer CYP2C19	Your body likely breaks down voriconazole slightly more slowly than normal, leading to somewhat higher drug levels. The standard dose is still recommended, but your doctor may monitor your levels.	CPIC Initiate therapy with recommended standard of care dosing. FDA Monitor drug levels closely and consider dose adjustment due to higher systemic concentrations.	Moderate
Likely Poor Metabolizer CYP2C19	Your body likely breaks down voriconazole very slowly, causing the drug to build up to high levels that increase the risk of side effects. A different antifungal medication is recommended, or a lower dose with close monitoring.	CPIC Choose an alternative agent that is not dependent on CYP2C19 metabolism as primary therapy in lieu of voriconazole. Such agents include isavuconazole, liposomal amphotericin B, and posaconazole. In the event that voriconazole is considered to be the most appropriate agent, based on clinical advice, for a patient with poor metabolizer genotype, voriconazole should be administered at a preferably lower than standard dosage with careful therapeutic drug monitoring. FDA Monitor drug levels closely and reduce dose. Consider alternative antifungal therapy if adverse reactions occur.	Strong
Indeterminate CYP2C19	The impact of your genotype on response to this drug is unknown	CPIC + FDA Initiate therapy with recommended starting dose.	—
Not available CYP2C19	The impact of your genotype on response to this drug is unknown	CPIC + FDA Initiate therapy with recommended starting dose.	—

Sources: CPIC, FDA

The gene behind the guidance

CYP2C19 Cytochrome P450 2C19

CYP2C19 handles several SSRIs (citalopram, escitalopram, sertraline), proton pump inhibitors (omeprazole, esomeprazole), and the blood thinner clopidogrel. About 2 to 5 percent of people of European descent and 15 to 20 percent of people of East Asian descent are poor metabolizers. Another 30 percent carry a rapid-metabolizer variant.

Rapid metabolizers clear affected drugs before they reach therapeutic levels. Poor metabolizers accumulate the drug and feel stronger effects.

See all drugs affected by CYP2C19 →

Related medications

Find out how your genetics affect Vfend

This page describes the general pharmacogenetics. A Gene2Rx report analyzes your own DNA to tell you which metabolizer group you fall into, across every medication.

Get your report Look up another medication

Informational only — not medical advice. Pharmacogenetic guidance describes population-level patterns; your individual response depends on many factors. Never start, stop, or change a medication without talking to your prescribing clinician.