Antifungal (Azole)

Fluconazole

Brand names: Diflucan

Fluconazole is a triazole antifungal for candidal infections (including vaginal and oral thrush) and some systemic fungal infections.

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.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION Dosage and Administration in Adults: Single Dose Vaginal candidiasis: The recommended dosage of fluconazole for vaginal candidiasis is 150 mg as a single oral dose. Multiple Dose SINCE ORAL ABSORPTION IS RAPID AND ALMOST COMPLETE, THE DAILY DOSE OF FLUCONAZOLE IS THE SAME FOR ORAL AND INTRAVENOUS ADMINISTRATION. In general, a loading dose of twice the daily dose is recommended on the first day of therapy to result in plasma concentrations close to steady-state by the second day of therapy. The daily dose of fluconazole for the treatment of infections other than vaginal candidiasis should be based on the infecting organism and the patient’s response to therapy. …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-11-17. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It inhibits fungal ergosterol synthesis (14-alpha-demethylase), disrupting the fungal cell membrane.

Prescribing in practice

It is a CYP inhibitor with interactions (e.g. warfarin, some statins) and can prolong the QT interval.
Hepatotoxicity can occur; reduce the dose in renal impairment for multi-dose courses.
Higher or repeated doses in pregnancy are associated with birth defects — avoid in pregnancy other than where specifically advised.

Monitoring

Monitor liver function with longer courses; review interactions.

Counselling the patient

Tell your clinician your other medicines.
Report yellowing of the skin or eyes.
Seek advice if you are pregnant or planning pregnancy.

Evidence & guidelines

Standard treatment for candidal infections (NICE CKS), with interaction and pregnancy cautions.

Reference: MHRA Drug Safety Update 2018 (Fluconazole in Pregnancy); 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).

Curated clinical cross-links plus same-class fallbacks.

Pathways