Voriconazole belongs to the family of medications called antifungals. It is used to treat certain types of invasive (inside the body) fungal infections, specifically Aspergillus or Candida infections. It works by preventing the fungus from growing.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult starting dose of voriconazole is either 200 mg or 400 mg, taken 12 hours apart for the first 24 hours. After the first 24 hours, the recommended dose is 100 mg or 200 mg, taken twice daily. For both the starting dose and the maintenance dose, the dose used depends on your body weight and the type of infection. Your dose may be adjusted by your doctor depending on how you respond to voriconazole and the side effects you experience.

Voriconazole tablets should be taken 1 hour before or 2 hours after a meal.

Voriconazole oral suspension must be taken 1 hour before or after a meal.

If you are using the oral suspension, shake the closed bottle for approximately 10 seconds before each use. The suspension should only be administered using the oral dispenser supplied with each pack.

Voriconazole oral suspension should not be mixed with any other medication or flavouring agent and it should not be further diluted with water or any other drinks.

Injection: The dose for voriconazole intravenous (into the vein) injection depends on body weight and the type of infection. Your doctor will determine the right dose for you. The dose is usually injected slowly into a vein over 1 to 2 hours in a clinic setting (e.g., hospital). Your dose may be adjusted by your doctor depending on how you respond to voriconazole and the side effects you experience.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

Your dose may be adjusted by your doctor depending on how you respond to voriconazole and the side effects you experience.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, skip the missed dose and continue with your regular dosing schedule.

Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Voriconazole tablets and oral suspension, as well as the injectable forms of this medication, should be stored at room temperature. Keep it out of reach of children. Safely discard any suspension that is left over after 14 days.

Do not take voriconazole if you:

• are allergic to voriconazole or any ingredients of the medication (It is not known if people who are allergic to other "azole" antifungal medications [e.g., ketoconazole, fluconazole, and itraconazole] will also be allergic to voriconazole.)
• are also taking any of the following medications:
• carbamazepine
• efavirenz
• ergot alkaloids (ergotamine and dihydroergotamine)
• eszopiclone
• ivabradine
• lovastatin
• lurasidone
• midazolam
• naloxegol
• pimozide
• quinidine
• rifabutin
• rifampin
• ritonavir
• simvastatin
• sirolimus
• St. John's wort
• tolvaptan
• triazolam
• venetoclax

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• back pain
• diarrhea
• eye pain or irritation
• fever
• hair loss
• headache
• itchiness
• nausea
• rash
• stomach pain
• vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• bone pain
• sensations of burning, tingling, or numbness
• chest pain or tightness
• feeling faint
• difficulty breathing
• dizziness
• flu-like symptoms (e.g., fever, chills, flushing, sweating, cough)
• hallucinations (e.g., seeing, hearing, or feeling things that are not actually there)
• increased sensitivity of the skin to the sun
• joint pain
• irregular or rapid heartbeat
• signs of kidney problems (e.g., decreased urination, nausea, vomiting, swelling of the feet and ankles)
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• swelling of the hands and feet
• symptoms of heart problems (e.g., shortness of breath, tiredness and weakness, cough, lack of appetite, nausea, decreased ability to exercise, swelling in ankles, legs, and feet)
• symptoms of liver problems (e.g., yellow eyes or skin, itching, unusual tiredness or weakness, stomach pain, nausea, vomiting)
• symptoms of low sodium levels in the blood (e.g., achy, stiff, or uncoordinated muscles; confusion; tiredness; weakness)
• tingling
• vision changes (e.g., blurry vision, colour vision change, reduced vision, increased sensitivity of the eyes to light)
• weakness

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of a severe allergic reaction (e.g., itching; skin rash or blisters; shortness of breath; difficulty breathing; swelling of the face, lips, or tongue)
• symptoms of a severe skin reaction (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: This medication can cause abnormal heart rhythms. Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, probucol, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with voriconazole. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are older than 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

If you have heart disease and abnormal heart rhythms, or are taking certain medications, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Adrenal gland problems: Adrenal glands produce chemical messengers that are responsible for the normal function of the body’s organs, including how your body responds to injury or stress. On rare occasions, voriconazole may affect your adrenal glands. If you experience unusual acne, increased blood pressure, mood changes or depression, increased blood sugars, or muscle and bone weakness, let your doctor know as soon as possible.

Allergy: It is not clear whether people who have previously had an allergic reaction to another "azole" antifungal will have an allergic reaction to voriconazole. Make certain all medical professionals involved in your care know if you have had an allergic reaction to a different antifungal medication in this class, before taking voriconazole.

Contact your doctor at once if you experience signs of an allergic reaction, such as skin rash, itching, difficulty breathing, or swelling of the face and throat.

Bone health: Some people taking voriconazole who have had transplants have reported bone inflammation. If you experience unusual or intense pain in your back, legs, or arms, or difficulty standing because of pain, contact your doctor as soon as possible.

Driving/hazardous activities: Voriconazole can cause changes to vision, affecting your ability to drive or participate in other activities. Avoid driving or other potentially hazardous activities until you know how this medication affects you. Do not drive at night while taking voriconazole.

Infusion-related problems: Reactions may occur during the infusion of the intravenous formulation of voriconazole. These include flushing, fever, sweating, rapid heart rate, chest tightness, difficulty breathing, feeling faint, nausea, itching, and rash. Report these to your doctor if they occur, as the infusion may have to be stopped.

Kidney problems: Rarely, voriconazole has been linked to developing kidney problems. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Signs of decreasing kidney function include the production of very small amounts of urine, swelling in your legs and feet, loss of appetite, nausea, vomiting, confusion and anxiousness, or excessive sleepiness. If you notice any of these, contact your doctor as soon as possible.

Lactose: Voriconazole tablets contain lactose. If you have or suspect you have galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption, voriconazole tablets may worsen your condition.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. As well, voriconazole may reduce liver function and can cause liver failure. Your doctor will monitor the function of your liver while you are taking this medication. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Although serious liver reactions have been rare, contact your doctor if you notice signs of liver problems such as unusual fatigue, loss of appetite, nausea or vomiting, yellowing of the skin or eyes, dark urine, or pale stools. If you have severe liver cirrhosis, voriconazole should only be used if the benefits outweigh the risks, and you should be closely monitored by your doctor while you are taking the medication.

Pancreatitis (inflammation of the pancreas): Voriconazole may cause or worsen pancreatitis. If you have a history of or are at risk for developing pancreatitis (i.e., have had chemotherapy or a stem cell transplant), you should be closely monitored by your doctor while taking this medication. If you develop signs of pancreatitis (e.g., upper left abdominal pain, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen), contact your doctor.

Skin reactions: In rare cases, people have had skin reactions when they have taken this medication. If you get a skin rash that worsens, or if you experience exfoliating skin conditions such as peeling, shedding, or scaling of the skin, or any other unusual reaction of the skin, contact your doctor immediately. Your skin may also become sensitive to sunlight. Try to avoid strong sunlight while taking this medication.

Melanoma and squamous cell carcinoma, types of skin cancer, have been reported with long term use of voriconazole. Check your skin regularly for new moles or moles that are changing. If it grows, changes colour, is bleeding, or is otherwise unusual, contact your doctor to have it examined.

Vision changes: Voriconazole may cause blurry vision, reduced vision, colour vision change, and increased sensitivity of the eyes to sunlight. Most visual symptoms should clear up within 60 minutes. Avoid driving or operating machinery if you experience any changes in vision. Do not drive at night while taking voriconazole.

Pregnancy: Voriconazole can cause harm to the fetus when the medication is taken during pregnancy. Voriconazole should not be used during pregnancy. People who may become pregnant should always use an effective form of birth control during treatment with voriconazole. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if voriconazole passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 12 years of age.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.