Voriconazole (Oral)

Voriconazole, also known by its trade name of VFend, is a drug that is used to treat invasive fungal and yeast infections including aspergillosis and candidemia in the blood, lungs and other areas of the body.


Voriconazole is a drug that helps to reduce the symptoms of fungal and yeast infection in patients. The drug is marketed under the trade name of Vfend and was first introduced to the American market in 2002 after it was approved by the FDA.

Conditions treated

Type of medicine

  • Triazole antifungal

Side Effects

In common with many drugs that are used to treat serious conditions, Voriconazole has a number of side effects which can be fairly unpleasant. Normally, a doctor will have to weigh up the advantages of using Voriconazole against these fairly severe side effects. In some cases, doctors will try to prescribe Vfend to patients on an intermittent basis in order to allow them to enjoy some months of the year without suffering from the side effects of using the drug. In the case of some lung conditions, it can be possible to only use Vfend during the colder months of the year and come off the drug or move to a less strong alternative during the summer months. Every patient is different and it is rare for a patient that has been prescribed Voriconazole to have straightforward medical needs. Usually, the complexity of the case will require a highly individualized plan to be drawn up before the patient can begin taking Vfend.

The complexity of patients' conditions means that side effects can vary significantly between one person who is taking Vfend and another. Nevertheless, there are a number of side effects that all patients and doctors are primed to keep an eye out for based on the literature that is provided when Vfend is first prescribed. As with most drugs, the side-effects are categorized based on how intrusive, serious and long-lasting they can be. None of the side-effects are pleasant but some can be managed more easily than others. In some cases, the side-effect may pass after a few days on the treatment, in others it may persist throughout and beyond the patient's usage of Vfend.

Some of the minor side-effects that can be experienced when taking Voriconazole include:

  • Nausea - this sometimes only lasts for a few days after the patient begins taking the drug. However, in some cases, the symptoms can persist throughout the course of treatment. These can be alleviated when the patient makes certain lifestyle changes or alterations to their diet.
  • Diarrhea - Again, these symptoms can last for a few hours or days after the course of treatment first starts or may persist for the entire period that the patient is taking the drug. As with the case of nausea, the symptoms can be alleviated by changing diet or lifestyle. It's also possible to treat the condition with common anti-diarrhea medication. However, as with all drugs that are prescribed in combination with Voriconazole, it's key that the physician is sure that there is no risk of negative interaction with whatever medication they have prescribed to deal with this side-effect.
  • A headache - This can be short-term or longer-lasting. While it can be treated with over the counter medication, it's important to be certain that there is no risk of negative interactions before starting any course of additional drugs.
  • Fever - Again this may only impact a patient when they first start taking the drug or may come and go all the way through the patient's course of treatment with Vfend. While the symptoms can be relieved with common over the counter fever medication, it is essential that a patient checks for any negative interaction and has a conversation with their doctor before they begin to self-medicate for any of the side-effects that have been caused by their Vfend.
  • Swollen feet, ankles or hands. These will generally come and go over the course of the treatment. If you are taking Vfend in combination with long-term steroid use (as is often the case for certain conditions) the Vfend may exacerbate any existing weight gain or swelling. Diet changes can help but have fairly limited utility, particularly as steroid use often leads to an increased appetite.

While the conditions mentioned above can be unpleasant to experience, they are expected when a patient is taking Vfend and can generally be managed effectively by a patient and doctor working together. There are also a number of more serious side effects that can point to underlying problems and may require your prescription to be changed or the course of Vfend to be stopped earlier than was originally intended. If you experience any of the side effects listed in the following section, tell your doctor as soon as possible:

  • Vision Changes - Voriconazole can cause vision changes of various types. Some patients have described this as similar to seeing 'fireworks when their eyes are closed'. The patient may also experience color vision changes, photophobia (a more general sensitivity to bright lights) and blurred vision. While it's easy to let this kind of changes blend into the background after a while, they can often be a sign of more serious problems, so it's important that the patient tells their doctor about them as soon as you have the chance to do so.
  • Easy bleeding or bruising - Again, this is a condition that a patient may already be familiar with if they are taking steroids to deal with other health issues. However, if the phenomenon significantly worsens when they start their course of Vfend, it is important that the patient and doctor have a discussion about it so that alternative types of treatment can be considered.
  • Mental/mood changes - If a patient has been newly diagnosed with a condition such as aspergillosis, then it is entirely natural for them to experience mood changes. However, it's important that a patient takes time to track their mood after they start your course of Vfend in case it causes any specific issues on its own.
  • Tiredness - Again, it can be hard to tell when this is a particular side effect of using Vfend or just a reaction to a new diagnosis with a serious infection. If the symptoms persist for a significant period of time after the patient has begun their course of treatment, then it is recommended that the patient and doctor have a discussion about the severity of the tiredness, whether there are any other drugs that could help to deal with these problems and any other options that the doctor may be able to suggest.
  • Sudden behavior changes/problems with speech or thinking - Again, it can be difficult for a patient to diagnose these problems in themselves. It is recommended that families and close friends are made aware of the potential for this side effect to occur so they can quickly raise any concerns with the patient when required. As with many of the side-effects of Vfend, this one will require a judgement call to be made by the doctor who is treating the patient as to whether the side-effects are severe and long-lasting enough to merit intervention and changes to treatment plans or whether there is a chance that they will fade over time once the patient's body becomes more used to the effects of taking Vfend.

Vfend is a serious drug and the patient will almost certainly have regular meetings with their doctor to discuss their progress after they begin taking the drug. It's also important that the patient takes time to note down any side effects as and when they occur, as it can be easy to forget about issues once the symptoms have stopped. The more information that a patient is able to give their doctor about how their course of treatment is progressing, the better the chances of a successful outcome.


As with all drugs that have been passed as fit by the FDA, there is specific advice on the doses in which Voriconazole should be taken in order to achieve the best results for the patient. Vfend should be taken in 200mg capsule form or as a powder with the same weight. It can be taken up to twice daily, depending on the severity of the condition being treated.

In some cases, it is necessary to modify the dosage of Voriconazole depending on the weight of the patient being treated. As with all drugs, large doses will overwhelm a smaller person much more quickly than a larger person and attention has to be paid to the patient's weight and metabolism when prescribing decisions are first being made. Similarly, it is possible to increase the dose of Vfend from 200mg to 300mg if the initial response of the patient to the drug is inadequate. If the desired outcome is still not achieved, then doctors will often consider similar drugs in its class which can work in slightly different ways and may be more effective when taken by a particular patient.

Drug Interactions

Voriconazole can have serious and negative interactions even with fairly commonplace drugs. Therefore, it's absolutely essential that the patient's physician is aware of all the drugs they are taking before Voriconazole is prescribed. In many cases, it will be necessary to substitute or even entirely discontinue the use of other drugs before voriconazole can be prescribed.

Voriconazole is not the only drug in its class and doctors will generally take time to compare it against its alternatives before deciding whether or not to prescribe it. The existing cocktail of drugs that a patient is taking will often push them in one direction over another.

Unfortunately, knowledge of Voriconazole and similar antifungal drugs can be low among certain doctors due to the rarity of the conditions that they are used to treat. To this end, a British charity has created a mobile app that is designed for use by both patients and doctors which identifies drugs which Voriconazole will interact negatively with. The list is not exhaustive and the app is not entirely suited to the American medical system due to the different names that are used for certain common drugs in the UK (Tylenol is known as paracetamol, for example). Nevertheless, it can be a useful starting point for patients and doctors who are new to the drug and want to be certain that their prescriptions are not causing unnecessary risk.

While it is necessary to examine each patient's prescriptions individually, it's worth being aware of some key drugs with which Voriconazole has been known to have negative interactions. Some of these include:

  • Nexium
  • Zofran
  • Prograf
  • Protonix

The list above is far from exhaustive and, if you're a patient that has been newly diagnosed with the condition, we'd highly recommend taking a little time to make sure that you're familiar with the drug's interactions before you next discuss the condition and the treatment plan with your physician. If you don't have access to an iPhone, then the Voriconazole drugs interaction list provided by Drugs.com is a good place to start. The FDA also provides a regularly updated list of the drug's interactions which is worth regularly consulting as new drugs hit the market.


As we have explored above, the benefits of taking Vfend can come with significant downsides if the course of treatment is not carefully monitored by both the patient and the physician. Before treatment starts, it is essential that the doctor carries out a drug audit to ensure that there is no chance of negative interactions between Vfend and another drug that the patient has previously been given causing harm to the patient. This can be the case even with fairly common drugs, so it is of vital importance that this is carried out before the treatment begins.

With a drug like Voriconazole, the positive impact of the drug builds over the course of the treatment. Therefore, it is vitally important that the patient sticks to the dosage plans and guidelines that they have been given by their doctor. Missing an individual tablet can cause a patient to lose the progress they have made and could give the infection that Vfend was prescribed to treat a chance to make a comeback. As aspergillosis and other conditions that are treated with Voriconazole can act very quickly when they are given the chance to, it is very important that the patient never misses a dose.

Practical steps can be taken to reduce the risk of this happening. As doses are taken at the same time every day, it is possible to use smartphone apps or even simple alarms on digital watches to manage the administration of Vfend. If it is taken in combination with a number of other drugs, then using a pill box can be a good way to ensure that no dose is ever forgotten and the drug is given the best possible opportunity to perform effectively on behalf of the patient.


Voriconazole is a powerful drug that can help to significantly prolong the life of patients who are prescribed it. However, taking Voriconazole generally means that a patient has to become much more medically aware as the drug can have severely negative interactions if the cocktail of drugs being taken is not carefully monitored by a doctor.

While the side-effects of Vfend can be very unpleasant, as with all drugs, there is a trade-off to be made between these side-effects and the benefits of taking the drug. Since Voriconazole is often the only drug that stands between a patient with a severe fungal or yeast infection and death, it will often be necessary for the patient to endure fairly severe side-effects during the course of treatment. This can sometimes be mitigated by discontinuing the use of Vfend for short to medium-length periods when the patient is generally in better health.

When taken correctly and monitored regularly, Voriconazole can make a huge difference to the health and overall prospects of a patient. It may allow them to discontinue regular or permanent use of oxygen supplies and return to living a much more normal quality of life than was possible before the course of treatment began.

Vfend is a serious drug that is used to treat serious conditions and it is important that both patient and doctor treat it with respect. It should not be prescribed on a whim and it is absolutely essential that the patient sticks to the treatment plan that they are given. Side effects must be closely monitored and if a patient is seeing multiple doctors for treatment of various conditions, it is vital that they communicate about the patient's usage of Voriconazole to avoid any prescribing mistakes that could cause major health issues for the patient.


Last Reviewed:
December 24, 2017
Last Updated:
April 04, 2018
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