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Antifungal — Aspergillosis Prophylaxis / Salvage

Posaconazole

Brand names: Noxafil

Posaconazole is a broad-spectrum triazole antifungal used in respiratory and haematology practice for prophylaxis and treatment of invasive fungal infections including aspergillosis. It is available as gastro-resistant tablets, oral suspension and an intravenous form.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It inhibits fungal lanosterol 14-alpha-demethylase, blocking ergosterol synthesis and disrupting the fungal cell membrane.

Prescribing in practice

  • Posaconazole is a potent CYP3A4 inhibitor and prolongs the QT interval, so screen for interacting and QT-prolonging drugs and avoid contraindicated combinations before prescribing.
  • The tablet, suspension and intravenous formulations are not interchangeable and have different administration requirements, so prescribe by formulation.
  • Monitor liver function and correct electrolyte disturbances such as low potassium or magnesium that increase arrhythmia risk.

Monitoring

Monitor liver function, electrolytes and ECG where indicated, with plasma-level monitoring used in selected patients to confirm adequate exposure.

Counselling the patient

  • Tell your team about all other medicines, as posaconazole interacts widely.
  • Take the suspension with food and the tablets as directed, and do not swap between them.
  • Report yellowing of the skin or eyes, palpitations or feeling faint.

Evidence & guidelines

UK guidance and the SPC support posaconazole for prophylaxis and treatment of invasive fungal infections in at-risk patients.

Reference: Cornely et al. NEJM 2007 (posaconazole prophylaxis AML); ESCMID/ECMM/ERS Aspergillosis Guidelines 2018; NICE; SPC Noxafil; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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