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, droperidol, pimozide, gatifloxacin, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, dolasetron mesylate, 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.
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.
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.
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. Women 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 a breast-feeding mother and are 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.