Voriconazole

Note: For haemato-oncology patients see management and prevention of invasive fungal infection (IFI) in adult haemato-oncology patients guideline

Intravenous: Use ideal body weight to calculate dose. Carry out therapeutic drug monitoring.

Renal impairment

• Oral: No dose adjustment required 
• IV: No dose adjustment required. If creatinine clearance is less than 50 mL/min accumulation of the intravenous vehicle sulfobutylether-β-cyclodextrin (SBECD) can occur. 
  • Consider if oral voriconazole can be used. Oral voriconazole has up to 96% bioavailability if taken on an empty stomach. 
  • If IV used, monitor serum creatinine and if increases occur review use of IV voriconazole and consider changing to oral voriconazole or alternative antifungal. Discuss with Micro/ID.

Hepatic impairment

• Mild to moderate hepatic cirrhosis (Child-Pugh A and B): Use standard loading dose and then half the maintenance dose. 
• Severe hepatic cirrhosis (Child-Pugh C): Voriconazole has not been studied in this group of patients. Use only if the benefit outweighs the potential risk. Monitor patient for side effects.

Therapeutic Drug Monitoring is required. See Therapeutic Drug Monitoring (TDM) for Antifungal Agents

Before voriconazole is started see the Summary of Product Characteristics (SPC) for voriconazole for information about interactions, cautions and contraindications.

• Voriconazole is metabolised by, and inhibits the activity of, cytochrome P450 isoenzymes, CYP2C19, CYP2C9, and CYP3A4. 
• The co-administration of voriconazole with several medications is contraindicated. See SPC for more information.
• Caution is recommended for the use of voriconazole with several medications. See SPC for more information.
• Some medications require a dose adjustment of voriconazole when they are used concomitantly. See SPC for more information.

Contraception: Woman of childbearing age MUST use effective contraception during treatment with voriconazole. Interactions may exist between voriconazole and oral contraceptive treatments. See SPC for more information.

Pregnancy: Manufacturer recommends avoid unless potential benefit to mother outweighs potential risk to foetus. Insufficient data in pregnant people. Toxicity shown in animal studies.

Breastfeeding: Women should not breastfeed whilst taking voriconazole. No reports available. Likely to be excreted into breast-milk.

• The MHRA Drug Safety update in December 2014 'Voriconazole: reminder of risk of liver toxicity, phototoxicity, and squamous cell carcinoma' (HERE) has information for healthcare professionals which includes monitoring and counselling for patients. There is also a link to the Patient Alert Card 
• Voriconazole should be administered with caution to patients with potentially proarrhythmic conditions.
• Monitor LFTs before voriconazole is started, then at least weekly for one month, and then monthly if there are no changes in the first month of treatment. Consider treatment discontinuation if severe abnormalities in LFTs.
• Monitor U&Es. If IV preparation and creatinine clearance is less than 50 mL/min see renal dosing section above.
• There have been reports of prolonged visual adverse reactions, including blurred vision, optic neuritis and papilloedema in patients that recieve voriconazole. Patients should be advised to seek medical advice if these occur.
• The OUH Antifungal Patient Information Leaflet can be found HERE

1. Pfizer Limited. Summary of Product Characteristics. Voriconazole Pfizer 200mg powder for solution for infusion [online]. Last revision of the text: 5/23. Accessed via: www.emc.medicines.org.uk Accessed 21/3/25
2. Pfizer Limited. Summary of Product Characteristics. Vfend 200mg film-coated tablets [online]. Last revision of the text: 11/24. Accessed via: www.emc.medicines.org.uk Accessed 21/3/25
3. Pfizer Limited. Summary of Product Characteristics. Vfend 40mg/ml powder for oral suspension [online]. Last revision of the text: 09/24. Accessed via: www.emc.medicines.org.uk Accessed 21/3/25
4. The Renal Drug Database. Voriconazole. [online]. Last updated: 29/10/24. Accessed via: https://renaldrugdatabase.com Accessed 21/3/25
5. Sanford Guide. Voriconazole [Internet] Last updated: 18/2/25. Accessed 21/3/25
6. Sanford Guide. Obesity dosing adjustment [Internet] Last updated: December 2024. Accessed 21/3/25
7. Luke, David R et al. “Review of the basic and clinical pharmacology of sulfobutylether-beta-cyclodextrin (SBECD).” Journal of pharmaceutical sciences vol. 99,8 (2010): 3291-301. doi:10.1002/jps.22109
8. Eljaaly, K., & Nix, D. E. (2016). Voriconazole Dosing in Obese Patients. Clinical infectious diseases: an official publication of the Infectious Diseases Society of America, 63(2), 286–287. https://doi.org/10.1093/cid/ciw252