Voriconazole

What Is Voriconazole?

Voriconazole is a prescription antifungal medicine. It belongs to a group of medicines called triazole antifungals (often called “azole” antifungals). It is sold under the brand name Vfend and as generic versions. It is mainly used for serious fungal infections, often in people with weakened immune systems.

FDA-Approved Uses

Voriconazole is approved to treat:

• Invasive aspergillosis, a serious infection caused by Aspergillus mold, usually in the lungs
• Candidemia (Candida in the bloodstream) in people without a very low white blood cell count, and certain Candida infections that have spread to the skin, abdomen, kidney, bladder, or wounds
• Esophageal candidiasis, a yeast infection of the esophagus
• Serious infections caused by Scedosporium apiospermum and Fusarium species, in patients who cannot tolerate or have not responded to other treatments

Other Prescribed Uses

Specialists sometimes use voriconazole for other fungal infections, or to help prevent fungal infection in some high-risk patients, based on individual circumstances. These decisions belong to the treating specialist.

Available Forms and Strengths

• Tablets: commonly 50 mg and 200 mg
• Oral suspension (liquid): 40 mg/mL after the pharmacy mixes the powder with water
• Intravenous (IV) solution: a powder mixed into a solution and given through a vein in a hospital or clinic

Available strengths can vary by manufacturer and country.

What Is the Recommended Dosage of Voriconazole?

There is no single dose that fits everyone. The prescribed dose and length of treatment depend on several factors:

• The condition being treated. Treatment for serious fungal infections often lasts weeks to months.
• Age. Children are dosed differently from adults, and the medicine is approved for children 2 years and older.
• Body weight. Weight is often used to calculate the dose.
• Liver function. People with liver disease often need a lower maintenance dose.
• Kidney function. The IV form contains an ingredient that can build up in people with reduced kidney function, so the oral form may be preferred in some cases.
• Other medicines and individual differences in how the body breaks down the drug. Blood levels vary widely between people, so doctors sometimes check voriconazole blood levels to guide dosing.

Treatment often starts with a higher “loading” dose followed by a lower maintenance dose. The IV form is often used first, with a switch to tablets or liquid once the patient is stable.

Tablets and liquid are generally taken at least 1 hour before or 1 hour after a meal, because food can lower how much medicine the body absorbs. Take voriconazole exactly as your licensed medical specialist or pharmacist instructs. Do not change the dose, stop early, or extend treatment on your own, even if you feel better. Stopping too soon can allow the infection to return.

How Voriconazole Works

Fungal cells have a protective outer membrane, and a substance called ergosterol is an important part of it. Voriconazole blocks an enzyme fungi need to make ergosterol. Without enough ergosterol, the cell membrane becomes weak and the fungus cannot grow and multiply normally.

Voriconazole treats and controls fungal infections, but it does not work alone. It slows or stops the fungus, which helps the immune system clear the infection. How well it works depends on the type of fungus, the location of the infection, and the person’s overall health. It does not work against bacterial or viral infections.

Is a Prescription Required to Buy Voriconazole Online?

In the United States, voriconazole is a prescription-only medicine. A licensed healthcare professional must evaluate you before it is prescribed, and treatment is usually started and supervised by a specialist.

Depending on the infection, the specialist may be:

• An infectious disease specialist
• A pulmonologist (lung specialist)
• A hematologist/oncologist or transplant physician (for patients with cancer or transplants)
• Another specialist relevant to the site of infection

Only buy voriconazole from a licensed pharmacy that requires a valid prescription. Be careful with websites that sell it without one. Counterfeit, expired, or improperly stored products can be unsafe. Products labeled for animals are not approved for people and should never be used.

Side Effects of Voriconazole

Many people tolerate voriconazole well, but side effects can occur, and some are more common than with other antifungals.

Common Side Effects

• Vision changes, such as blurred vision, changes in color perception, or sensitivity to bright light. These often happen soon after a dose and usually go away.
• Fever or chills
• Nausea, vomiting, or diarrhea
• Headache
• Rash
• Swelling in the hands, feet, or legs
• Abnormal liver blood tests
• Seeing or hearing things that are not there (hallucinations), in some patients

Talk to your doctor or pharmacist if these bother you or do not go away. Because of possible vision changes, use caution when driving or operating machinery, especially at night.

Serious Side Effects

Serious reactions are less common but possible. Get medical help right away if you notice:

• Yellowing of the skin or eyes, dark urine, pale stools, or severe stomach pain (possible liver problems)
• A fast, pounding, or irregular heartbeat, or fainting (possible heart rhythm changes)
• Severe skin reactions, such as blistering, peeling, or mouth sores
• Swelling of the face, lips, tongue, or throat, or trouble breathing (allergic reaction)
• Severe or lasting changes in vision, or eye pain
• Severe sunburn or blistering after light sun exposure
• Ongoing bone pain, especially with long-term use
• Extreme tiredness, weakness, low blood pressure, or vomiting that does not stop (possible adrenal gland problems)
• Severe stomach pain with nausea (possible pancreatitis)
• Confusion, severe mood changes, or seizures

Call emergency services if you have trouble breathing or think you are having a life-threatening reaction.

Drug Interactions

Voriconazole is broken down by certain liver enzymes and also affects those same enzymes. This means it can change the levels of many other medicines, and other medicines can change voriconazole levels. Some combinations are not allowed. Major categories include:

• Medicines that lower voriconazole levels and are generally not allowed with it, such as rifampin, rifabutin, carbamazepine, and long-acting barbiturates (phenobarbital)
• Medicines that affect heart rhythm (certain antiarrhythmics, some antibiotics, some antipsychotics), which can increase the risk of dangerous rhythm changes
• Immune-suppressing medicines (such as tacrolimus, cyclosporine, and sirolimus, which is not allowed with voriconazole)
• Blood thinners (such as warfarin), which may increase bleeding risk
• Seizure medicines (such as phenytoin)
• Cholesterol medicines (statins), which may raise the risk of muscle problems
• Diabetes medicines (sulfonylureas), which may cause low blood sugar
• Sedatives and sleep medicines (certain benzodiazepines)
• Opioid pain medicines (such as methadone, oxycodone, and fentanyl)
• HIV medicines (such as efavirenz and ritonavir)
• Stomach acid reducers, including proton pump inhibitors such as omeprazole
• Certain cancer medicines
• Calcium channel blockers and other blood pressure or heart medicines
• Hormonal birth control
• Ergot medicines, used for migraine

Tell your provider about all over-the-counter medicines (including NSAIDs such as ibuprofen), vitamins, supplements, and herbal products. St. John’s wort is a well-known herbal product that must not be combined with voriconazole. Also mention alcohol use.

Give your licensed medical specialist and pharmacist a complete, up-to-date list of everything you take. This list is not complete, so always check before starting or stopping any medicine.

Safety & Important Considerations

• Liver disease: Voriconazole can affect the liver. Liver blood tests are usually done before and during treatment. Dose changes may be needed for people with liver disease.
• Kidney disease: Kidney function is monitored, and the IV form may be avoided in people with significantly reduced kidney function.
• Heart conditions: Voriconazole can affect heart rhythm (QT prolongation). Extra caution applies to people with heart rhythm problems, heart failure, low potassium, magnesium, or calcium, or those taking other medicines with the same effect. Your doctor may check blood salts and an electrocardiogram (ECG).
• Sun sensitivity and skin cancer risk: Voriconazole can make skin very sensitive to sunlight. With long-term use, skin cancers have been reported. Avoid direct sunlight, use sunscreen, and wear protective clothing. Regular skin checks may be advised.
• Vision: Vision changes are common. With treatment longer than about 28 days, eye and vision monitoring may be recommended.
• Bone problems: Long-term use has been linked to bone changes and pain. Report unexplained bone or joint pain.
• Adrenal problems: Voriconazole can affect adrenal gland function in some patients.
• Pregnancy: Voriconazole can harm an unborn baby and is generally avoided in pregnancy unless the benefit outweighs the risk. Tell your provider if you are pregnant, may become pregnant, or are trying to conceive. Effective birth control is advised during treatment.
• Breastfeeding: It is not well established whether voriconazole passes into breast milk. Discuss the risks and benefits with your provider.
• Children: Voriconazole is used in children 2 years and older, with dosing determined by a specialist. Children may be more likely to have certain side effects, such as liver problems and rashes.
• Older adults: Older adults often take multiple medicines, which raises the chance of interactions.
• Lactose and sugar content: Tablets contain lactose, and the liquid contains sucrose. Tell your provider if you have an intolerance to these sugars.
• Alcohol: Ask your provider whether alcohol is safe, especially if you have liver concerns.

Who This Medication Is For

Voriconazole is prescribed for adults and children (2 years and older) who have a confirmed or strongly suspected serious fungal infection that is likely to respond to it, within its approved indications. Patients often have weakened immune systems, for example due to cancer treatment, organ or stem cell transplant, or other serious illness. Whether it is appropriate depends on the type of infection, medical history, other medicines, and test results.

Who Should Not Take Voriconazole

Voriconazole is not suitable for everyone. Do not take it if:

• You have had an allergic reaction to voriconazole. Tell your provider if you have reacted to other azole antifungals, since cross-reactions can occur.
• You take certain medicines that must not be combined with voriconazole, including rifampin, rifabutin, carbamazepine, long-acting barbiturates, sirolimus, pimozide, quinidine, ergot medicines, and St. John’s wort. A few other medicines are also not allowed. Your provider and pharmacist can check your list.

Use extra caution and discuss risks with your provider if you have:

• Liver or kidney disease
• A heart rhythm disorder, or a family history of one
• Low potassium, magnesium, or calcium levels
• A history of serious skin reactions, or skin cancer
• Sun sensitivity
• Pregnancy, plans for pregnancy, or breastfeeding
• Lactose intolerance (tablets) or sucrose intolerance (liquid)

What to Do If You Miss a Dose

• Take the missed dose as soon as you remember.
• If it is almost time for your next dose, skip the missed one and go back to your regular schedule.
• Do not take two doses at once to make up for a missed dose.
• Keep taking it on an empty stomach, as directed.
• If you are unsure what to do, or you miss several doses, contact your licensed medical specialist or pharmacist. Missed doses can affect treatment of a serious infection.

Related medications to Voriconazole

Other antifungal medicines exist, and the right one depends on the type and location of the infection. Only a licensed specialist can decide whether a different medicine is appropriate.

Other azole antifungals (same class):

• Itraconazole
• Fluconazole

Antifungals from other classes:

• Amphotericin B (including liposomal forms), usually given by IV for severe infections
• Echinocandins (such as caspofungin, micafungin, and anidulafungin), usually given by IV

Do not switch or stop voriconazole without talking to your licensed medical specialist.

Storage Instructions

• Tablets: Store at room temperature, generally between 59°F and 86°F (15°C and 30°C), in the original container. Keep them dry and protected from moisture and light. Avoid storing them in a bathroom.
• Oral suspension: Before mixing, store the powder at room temperature. After the pharmacy mixes it, keep it at room temperature and tightly closed. Do not refrigerate or freeze it. Shake well before each use, and use only the dosing device provided. Mixed liquid is usually discarded after about 14 days, so follow the pharmacy label.
• IV vials: These are stored and prepared by healthcare professionals.
• Child safety: Keep all medicines out of reach and sight of children and pets, preferably in a locked or high cabinet.
• Do not use medicine past its expiration date. Ask your pharmacist about safe disposal of unused or expired medicine.

Disclaimer:

This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Patients must consult a licensed medical specialist, such as an infectious disease specialist, pulmonologist, hematologist/oncologist, or transplant physician, depending on the type of infection, before starting, changing, or stopping treatment. Treatment decisions must be based on a full clinical evaluation by a qualified specialist. Information about dosing, strengths, and safety may change, so always follow the guidance of your prescriber and the current product labeling.