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Triazole Antifungal — Candida / Fungal Prophylaxis in Preterm Neonates Pregnancy: Avoid — associated with cardiac and skeletal defects (Antley-Bixler-like syndrome) with prolonged high-dose use; single-dose 150 mg appears safer but avoid in first trimester

Fluconazole (Paediatric)

Brand names: Diflucan

Adult dose

Dose: Invasive candidiasis: 400 mg loading then 200–400 mg daily; mucosal candidiasis: 50–150 mg daily
Route: Oral or IV
Frequency: Once daily
Max: 800 mg/day
Adult reference — see paediatric dose section

Paediatric dose

Dose: 3–6 mg/kg once daily (mucosal candidiasis: 3 mg/kg; invasive: 6–12 mg/kg) mg/kg
Route: Oral (suspension 50 mg/5 mL or 200 mg/5 mL) or IV
Frequency: Once daily
Max: 400 mg/day (invasive); 200 mg/day (mucosal); neonates: 6 mg/kg every 72 hours (<2 weeks, term); every 48 hours (2–4 weeks)
BNFc: neonatal fungal prophylaxis in VLBW infants (<1.5 kg) in high-risk NICUs — 3–6 mg/kg twice weekly shown to reduce invasive candidiasis without promoting resistance in UK settings. Oral suspension well-tolerated — take with or without food. Unlike IV amphotericin/echinocandins, fluconazole oral equivalent to IV bioavailability (>90%) — IV used when nil by mouth only.

Dose adjustments

Renal

CrCl <50 mL/min: reduce dose by 50% or extend interval (renally cleared)

Hepatic

Use with caution — hepatically metabolised; monitor LFTs

Paediatric weight-based calculator

BNFc: neonatal fungal prophylaxis in VLBW infants (<1.5 kg) in high-risk NICUs — 3–6 mg/kg twice weekly shown to reduce invasive candidiasis without promoting resistance in UK settings. Oral suspension well-tolerated — take with or without food. Unlike IV amphotericin/echinocandins, fluconazole oral equivalent to IV bioavailability (>90%) — IV used when nil by mouth only.

Clinical pearls

  • Candida species resistance: C. krusei is intrinsically resistant to fluconazole; C. glabrata often resistant (check MIC); C. auris — variable; always check sensitivities before starting fluconazole for invasive candidiasis
  • VLBW neonatal prophylaxis: fluconazole 3 mg/kg twice weekly for 6 weeks in NICUs with high invasive candidiasis rates reduces incidence without significant resistance emergence (IRCCS study); not universal recommendation — depends on local epidemiology
  • Oral candidiasis (nystatin failure): fluconazole 3 mg/kg once daily × 7 days; nystatin remains first-line for oral thrush (topical, non-systemic, safe)
  • Cryptococcal meningitis (HIV children): fluconazole consolidation 200 mg/day after amphotericin induction — lifelong maintenance until immune reconstitution on ART

Contraindications

  • Concurrent terfenadine, cisapride, pimozide, quinidine (QT)
  • Concurrent rifampicin (reduces fluconazole levels)
  • Hypersensitivity to azoles (cross-reactivity possible)

Side effects

  • GI disturbance (nausea, abdominal pain)
  • Elevated LFTs (hepatotoxicity — monitor)
  • QTc prolongation
  • Rash (including Stevens-Johnson — rare)
  • Headache

Interactions

  • CYP2C9 inhibitor: warfarin (enhanced INR), phenytoin (increased levels)
  • CYP3A4 inhibitor: ciclosporin/tacrolimus (increased immunosuppressant levels — monitor carefully)
  • Rifampicin — reduces fluconazole levels significantly

Monitoring

  • LFTs (weekly in intensive treatment)
  • Renal function (dose adjustment)
  • Electrolytes including potassium (QTc risk)
  • Candida culture and sensitivity
  • Clinical response

Reference: BNF for Children; ESCMID Candida Guidelines; BPNG Neonatal Antifungal Guidelines; NICE Preterm Birth Guidance NG25. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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