Voriconazole

About Voriconazole

Voriconazole is a triazole antifungal that slows the growth of fungi. The label approves it for adults and children 2 years of age and older with invasive aspergillosis; candidemia in patients without neutropenia, and other deep tissue Candida infections; esophageal candidiasis; and Scedosporium or Fusarium infections when other treatment failed or was not tolerated. The usual adult oral dose is 200 mg (5 mL of suspension) every 12 hours, which the prescriber may raise to 300 mg; adults under 40 kg take 100 mg, and children are dosed by weight. Doses are taken at least one hour before or after a meal, because food lowers absorption.

There is no boxed warning, but the warnings are substantial. Voriconazole can injure the liver, and it can prolong the QT interval and cause dangerous heart rhythms, especially when potassium, magnesium or calcium is low. Visual disturbances (blurring, changed color perception, light sensitivity) are common. Severe skin reactions have occurred; the drug makes skin sensitive to sunlight, and skin cancers have been reported with long-term use. The label also warns of kidney toxicity, adrenal problems, pancreatitis and harm to an unborn baby. It must not be taken with certain drugs whose levels it raises (among them sirolimus, pimozide and quinidine) or with inducers such as rifampin, carbamazepine and St. John’s wort. Common side effects include visual disturbances, fever, nausea, rash, vomiting, headache, abnormal liver tests and hallucinations.

Voriconazole is cleared by the liver enzymes CYP2C19, CYP2C9 and CYP3A4, and CYP2C19 varies genetically between people, so blood levels differ widely. The label calls for liver enzymes and bilirubin at the start, at least weekly for the first month and then monthly, and for monitoring of vision if treatment runs beyond 28 days. The dose is halved in adults with mild or moderate liver impairment and raised when phenytoin or efavirenz is taken alongside. Females who could become pregnant use effective contraception.

Taking Voriconazole

How to take it

Every 12 hours, at least one hour before or one hour after a meal. Shake the suspension for about 10 seconds, measure it with the oral dispenser supplied, and do not mix it with other liquids. Keep taking it until the prescriber says to stop, even if you feel well.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose. Do not take a double dose.

Storage

Tablets at room temperature, away from heat and moisture, out of reach of children. Refrigerate the unmixed suspension powder; once mixed, keep it at room temperature, do not refrigerate or freeze it, and discard it after 14 days.

Interactions to know about

Voriconazole changes the levels of many drugs cleared by CYP3A4, CYP2C9 and CYP2C19, and some are contraindicated (for example sirolimus, pimozide, rifampin and St. John’s wort). MedlinePlus names fluticasone, mometasone, ibuprofen and omeprazole as medicines to raise with the prescriber first. Tell any surgeon or dentist that you take it.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Voriconazole differs from pharmacy to pharmacy

Generic voriconazole tablets come from many manufacturers, but the drug is used by a narrow group of seriously ill patients, so few retail pharmacies keep it on the shelf or on a flat-price generic list. A pharmacy that orders it in for one prescription may quote it as a slow-moving item, while one that fills it regularly can quote much less for the same generic. A prescription that names Vfend and blocks substitution is filled at a brand price.

The suspension has fewer generic makers, is mixed by the pharmacy and is discarded 14 days after mixing, so the number of bottles dispensed shapes the quote. The usual adult dose is two 200 mg tablets a day, so the quantity written and the dispensing fee on each fill matter.

Ways to pay less for Voriconazole without insurance

• Ask for generic substitution; if the prescriber wrote Vfend, ask whether a generic can be dispensed.
• Once the dose is settled, ask whether the prescription can cover the expected length of the course, so you pay fewer dispensing fees.
• Compare more than one pharmacy, including those near hospitals or transplant centers that fill voriconazole often.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Voriconazole

1. 1.Which of my other medicines, including over-the-counter ones like ibuprofen or omeprazole, interact with voriconazole?
2. 2.When are my liver blood tests due, and which symptoms mean I should call right away?
3. 3.How do I measure my suspension, and when do I throw the bottle away?
4. 4.Is it safe for me to drive, and what should I do about sun exposure while I take it?

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