Vfend (Voriconazole) – Comprehensive Patient Information for Australia
Basic Product Information
| International Non-proprietary Name (INN) | Voriconazole |
|---|---|
| Australian Brand Names | Vfend®, Generic Voriconazole |
| Anatomical Therapeutic Chemical (ATC) Code | J02AC03 |
| Available Forms and Strengths | Tablets: 50 mg, 200 mg Oral suspension: 40 mg/mL Powder for intravenous infusion: 200 mg per vial |
| Manufacturers | Pfizer Australia Pty Ltd; other generic producers |
| Prescription Status | Prescription only medicine (Schedule 4, S4) |
Mechanism of Action
For Patients: Voriconazole is an antifungal medicine. It works by stopping the growth of fungi and yeast that can cause serious infections—especially in people with weakened immune systems, such as patients undergoing chemotherapy, transplant recipients, or those with HIV/AIDS.
For Specialists: Voriconazole is a triazole antifungal that inhibits the fungal cytochrome P450-dependent enzyme 14α-lanosterol demethylase, disrupting ergosterol synthesis and compromising cell membrane integrity in yeasts and moulds.
Pharmacokinetics
- Absorption: Rapid and extensive after oral administration with a bioavailability of >90% under fasting conditions.
- Metabolism: Extensive hepatic metabolism primarily via CYP2C19 (as well as CYP2C9 and CYP3A4 pathways).
- Elimination: Metabolites excreted mainly via urine; unchanged drug excretion minimal.
- Half-life: Approximately 6 hours in healthy adults; can be longer in certain populations.
- Duration of Action: Effective antifungal activity persists for 12–24 hours, necessitating dosing every 12 hours.
Use in Everyday Life and Best Practices
Voriconazole is most commonly prescribed for the treatment of severe fungal infections, such as invasive aspergillosis, serious Candida infections, and certain rare fungal diseases. It is typically used in hospitals but can also be continued at home under medical supervision.
- Adults: The usual starting oral dose is 400 mg every 12 hours for two doses, then reduced to a maintenance dose of 200 mg every 12 hours. Dosing may be adjusted based on your medical condition, other medicines taken, or drug levels in the body.
- Children: Dose is weight-based. Voriconazole is available as a suspension for children who cannot swallow tablets.
- Elderly: Dosing is generally the same as for adults unless there is liver or kidney impairment.
- Missed Dose: Take as soon as you remember, but do not double up. If it’s close to your next dose, skip the missed one.
Dosing in the Morning vs Evening
Voriconazole is most effective when taken at regular 12-hour intervals. There is no strong evidence suggesting significant benefit of morning versus evening dosing, but regular timing helps maintain steady levels in your body.
- Tip: Choose set times (e.g., 8am and 8pm) and use reminders to ensure you do not miss doses.
- Maintaining regular intervals helps avoid suboptimal blood levels or increased risk of side effects.
Taking With Food or on an Empty Stomach
Voriconazole should be taken on an empty stomach, either one hour before or one hour after a meal. Food (especially high-fat Australian favourites like meat pies or full English breakfasts) can significantly reduce absorption of the medicine, making it less effective.
- Advice: Coordinate doses with your meal schedule. If taken close to breakfast or dinner, plan to take your tablet before these meals.
Interaction Warnings
Voriconazole can interact with many common medicines, foods, and alcohol. Always inform your pharmacist or doctor about all medicines and supplements you are taking.
| Interacting Substance | Effect/Warning |
|---|---|
| Alcohol | Increases liver side effect risk – best avoided |
| Statins (e.g. simvastatin) | Risk of muscle toxicity – avoid or monitor closely |
| Warfarin | Increased risk of bleeding – INR monitoring required |
| Rifampicin, carbamazepine, phenytoin | Reduces voriconazole level – avoid combination |
| Oral contraceptives | Effectiveness can be reduced – use additional contraception |
| Certain antihistamines (terfenadine, astemizole) | Risk of serious heart rhythm changes – avoid |
| Herbal remedies (especially St John's Wort) | Can reduce voriconazole effectiveness |
| Grapefruit juice | Should be avoided as can alter drug metabolism |
Indications
| Official Indications (TGA-approved) |
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|---|---|
| Off-label Uses (with specialist supervision) |
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Dosing According to Clinical Indications
| Indication | Adults | Paediatrics (2-12 years) | Elderly (>65 years) |
|---|---|---|---|
| Invasive Aspergillosis | 400mg twice daily for 1 day, then 200mg twice daily | 9mg/kg twice daily (max 350mg/dose) | As per adult dosing (monitor closely) |
| Resistant Candidiasis | As above | As above | As above |
| Scedosporium/Fusarium spp. | As above, possibly higher doses if severe | As above | As above |
| Prophylaxis (Off-label) | 200mg twice daily | As above | As above |
Note: Dosing may be adjusted in patients with reduced liver function or for those experiencing side effects. A doctor's supervision is required at all times.
Safety Profile / Side Effects
| Very Common | Common | Rare/Serious |
|---|---|---|
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- Be alert: Contact your doctor if you notice yellowing of the skin or eyes, severe skin reactions, sudden breathlessness, or confusion.
- Routine blood tests may be required to monitor your liver, kidney, and drug levels, which is standard care in Australia.
Guidelines for Proper Use (Australia Focus)
- Only take voriconazole as prescribed by your doctor or infectious diseases specialist.
- Never share your medicine with others.
- Store tablets in a cool, dry place <25°C in Australia’s climate; suspension in refrigerator if opened (and discard after expiry).
- Follow all hospital or pharmacist instructions, including regular blood tests.
- Report any unusual symptoms to your pharmacist or GP immediately.
- Do not stop the medicine suddenly – always follow your doctor’s advice on stopping or switching treatment.
Alternative Treatment Options
- Posaconazole (Noxafil®): Used for invasive fungal infections, especially if voriconazole is not tolerated. Available on PBS for specific indications. More food-friendly formulation.
- Isavuconazole (Cresemba®): Newer azole, available in hospital use. Sometimes better tolerated in terms of liver and QT effects.
- Liposomal Amphotericin B (AmBisome®): IV medicine, preferred for some rapidly-progressing infections; higher risk of kidney side effects.
- Caspofungin (Cancidas®): IV echinocandin. Used for some refractory cases. Generally well tolerated but narrow spectrum compared to voriconazole.
Each antifungal has unique pros and cons. Voriconazole remains first-line for many invasive and resistant infections, especially for Aspergillus.
Legal, Registration, and Reimbursement Status in Australia
- Regulatory Authority: Registered by the Therapeutic Goods Administration (TGA)
- Reimbursement: Listed on the Pharmaceutical Benefits Scheme (PBS) under restricted or authority conditions for severe proven/probable invasive fungal infections
- Prescription Category: Schedule 4 (Prescription only)
- May be available through hospital supply for inpatients.
Latest Research and Clinical Guidance (2022–2025)
- Australian consensus guidelines (e.g., Australian Society for Infectious Diseases, 2023) support voriconazole as first-line for invasive aspergillosis and serious resistant Candida infections.
- Personalised dosing: Recent evidence recommends monitoring blood concentrations (“therapeutic drug monitoring”) to improve effectiveness and reduce side effects. (Ref: Clinical Microbiology and Infection, Dec 2023)
- Dose adjustments: Research supports dose modification in liver impairment and for patients with certain genetic backgrounds affecting drug metabolism (CYP2C19 polymorphism, 2024 update).
- Emerging pathogens: Ongoing studies in Australia (2024–2025) are evaluating efficacy in new or resistant strains, especially in immunocompromised populations (Ref: Medical Journal of Australia, June 2024).
Availability and Delivery
| Pack Size | Formulation | Indicative PBS Price (2024) | Delivery Times (Sydney, Melbourne, Brisbane, Perth, Adelaide) |
|---|---|---|---|
| 14 tablets / 200 mg | Film-coated tablet | $39.50 (PBS co-payment) | 1-2 business days |
| 50 mL oral suspension | Powder to mix | $39.50 (PBS co-payment) | 1-2 business days |
| 1 vial / 200 mg | IV powder | Hospital supply | Same-day/next day for major centres |
Availability may be faster in metropolitan areas; rural delivery within 2–4 business days. Ask your dispensing pharmacy for urgent supply if needed.
Frequently Asked Questions (FAQ)
- Can I take voriconazole with other medicines?
Always inform your doctor and pharmacist of all medicines, supplements, and herbal remedies you are taking. Voriconazole interacts with many medicines—never start or stop medicines without advice. - What should I do if I forget a dose?
Take the missed dose as soon as possible unless it’s almost time for your next dose. Do not double up doses. - Is it safe to drink alcohol while on voriconazole?
It is best to avoid alcohol, as both voriconazole and alcohol can affect liver function and increase side effect risk. - Can I drive or operate heavy machinery?
Voriconazole may cause visual disturbances or dizziness. Wait until you know how the medicine affects you before driving. - Is voriconazole safe in pregnancy or breastfeeding?
Voriconazole is not recommended during pregnancy or breastfeeding unless clearly prescribed by a specialist. Discuss alternatives with your doctor.
For individualised advice, always consult your doctor, specialist, or pharmacist. Regular medical monitoring and follow-up is essential for safe and effective treatment with voriconazole in Australia.
