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Triazole Antifungal — Candida / Fungal Prophylaxis in Preterm Neonates Pregnancy: No formal category stated. 'Fluconazole in standard doses and short-term treatments should not be used in pregnancy unless clearly necessary. Fluconazole in high dose and/or in prolonged regimens should not be used during pregnancy except for potentially life-threatening infections.' Observational studies suggest an increased risk of spontaneous abortion and a small increased risk of musculoskeletal malformations after first-trimester exposure; a meta-analysis of 5 observational studies found a 1.8–2 fold increased risk of cardiac malformations. Women of childbearing potential should be informed of the potential risk to the fetus; a 1-week washout is recommended after single-dose treatment before becoming pregnant, and contraception may be considered during longer courses and for 1 week after the final dose. Breast-feeding may be maintained after a single 150 mg dose but is not recommended after repeated use or high-dose fluconazole (§4.6).

Fluconazole (Paediatric)

Brand names: Diflucan

Paediatric use of fluconazole, a triazole antifungal, for candidal and other susceptible fungal infections including mucosal candidiasis and cryptococcal disease in children and neonates.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Indication-dependent: cryptococcal meningitis — loading dose 400 mg on Day 1, then 200 mg to 400 mg once daily; invasive candidiasis — loading dose 800 mg on Day 1, then 400 mg once daily; oropharyngeal or oesophageal candidiasis — loading dose 200 mg to 400 mg on Day 1, then 100 mg to 200 mg once daily; acute vaginal candidiasis or candidal balanitis — 150 mg as a single dose
Route: Oral (capsules or powder for oral suspension) or by intravenous infusion — 'On transferring from the intravenous to the oral route, or vice versa, there is no need to change the daily dose'. Capsules should be swallowed whole, independent of food intake
Frequency: Once daily for most indications; a single dose for acute genital candidiasis; once-weekly regimens for several dermatomycoses
Max: For cryptococcal meningitis, 'In life threatening infections the daily dose can be increased to 800 mg'; for coccidioidomycosis, '800 mg daily may be considered for some infections and especially for meningeal disease'. No absolute adult ceiling beyond these statements is given in §4.2
SOURCE: eMC UK SPC, productName 'Fluconazole 150 mg capsules', §4.2 (the SPC carries the full multi-indication posology table). Duration of therapy: cryptococcal meningitis usually at least 6 to 8 weeks; maintenance to prevent relapse of cryptococcal meningitis — 200 mg once daily indefinitely; coccidioidomycosis — 200 mg to 400 mg once daily for 11 months up to 24 months or longer; invasive candidiasis — generally 2 weeks after the first negative blood culture and resolution of signs and symptoms attributable to candidaemia; oropharyngeal candidiasis 7 to 21 days, oesophageal candidiasis 14 to 30 days (longer in severely compromised immune function); candiduria — 200 mg to 400 mg once daily for 7 to 21 days; chronic atrophic candidiasis — 50 mg once daily for 14 days; chronic mucocutaneous candidiasis — 50 mg to 100 mg once daily for up to 28 days; prevention of relapse of mucosal candidiasis in HIV patients at high risk — 100 mg to 200 mg once daily or 200 mg three times per week, indefinitely in chronic immune suppression; recurrent vaginal candidiasis (4 or more episodes a year) — 150 mg every third day for a total of 3 doses (days 1, 4 and 7) followed by 150 mg once weekly maintenance for 6 months; tinea pedis, corporis, cruris and candida skin infections — 150 mg once weekly or 50 mg once daily for 2 to 4 weeks (tinea pedis may need up to 6 weeks); tinea versicolor — 300 mg to 400 mg once weekly for 1 to 3 weeks, or 50 mg once daily for 2 to 4 weeks; tinea unguium (onychomycosis) — 150 mg once weekly until the infected nail is replaced; prophylaxis of candidal infections in prolonged neutropenia — 200 mg to 400 mg once daily starting several days before the anticipated onset of neutropenia and continuing for 7 days after the neutrophil count rises above 1000 cells per mm3. ELDERLY: adjust dosage based on renal function. Source §4.4, §4.6 and §4.8 were truncated at the source-fetch limit and §4.5 was not retrieved in full.

Paediatric dose

Route: Oral (an oral liquid formulation is more suitable in this population — 'The capsule formulation is not adapted for use in infants and small children') or by intravenous infusion
Frequency: Once daily — 'Fluconazole is administered as a single daily dose'. Term newborn infants have extended intervals: every 72 hours from 0 to 14 days of age and every 48 hours from 15 to 27 days of age
Max: 'A maximum dose of 400 mg daily should not be exceeded in paediatric population.' Term newborn infants 0 to 14 days — 'A maximum dose of 12 mg/kg every 72 hours should not be exceeded'; term newborn infants 15 to 27 days — 'A maximum dose of 12 mg/kg every 48 hours should not be exceeded'
dosePerKg is left null because the SPC gives per-kg RANGES by indication, not a single figure. VERBATIM §4.2, infants, toddlers and children (from 28 days to 11 years old): mucosal candidiasis — 'Initial dose: 6 mg/kg, Subsequent dose: 3 mg/kg once daily', the initial dose being used on the first day to reach steady state more rapidly; invasive candidiasis and cryptococcal meningitis — 'Dose: 6 to 12 mg/kg once daily' depending on severity of disease; maintenance therapy to prevent relapse of cryptococcal meningitis in children at high risk of recurrence — '6 mg/kg once daily'; prophylaxis of Candida in immunocompromised patients — '3 to 12 mg/kg once daily' depending on the extent and duration of the induced neutropenia. TERM NEWBORN INFANTS (0 to 27 days) excrete fluconazole slowly: give the same mg/kg dose as for infants, toddlers and children but every 72 hours (0 to 14 days) or every 48 hours (15 to 27 days); there are few pharmacokinetic data to support this posology. ADOLESCENTS (12 to 17 years): 'Depending on the weight and pubertal development, the prescriber would need to assess which posology (adults or children) is the most appropriate'; if treatment for genital candidiasis is imperative in this age group the adult posology should be used. EQUIVALENCE NOTE from §4.2: 'A dose of 100, 200 and 400 mg in adults corresponds to a 3, 6 and 12 mg/kg dose in children to obtain a comparable systemic exposure.' Safety and efficacy for the genital candidiasis indication in the paediatric population has not been established. Pharmacokinetics have not been studied in paediatric patients with renal insufficiency. Verify all under-18 dosing against a children's formulary.

Dose adjustments

Renal

Fluconazole is predominantly excreted in the urine as unchanged active substance. 'No adjustments in single dose therapy are necessary.' For patients (including the paediatric population) with impaired renal function receiving multiple doses, give an initial dose of 50 mg to 400 mg based on the recommended daily dose for the indication, then adjust the daily dose: creatinine clearance above 50 ml/min — 100% of the recommended dose; 50 ml/min or below (no haemodialysis) — 50%; haemodialysis — 100% of the recommended dose after each haemodialysis session, with a reduced dose according to creatinine clearance on non-dialysis days.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance, to related azole substances, or to any of the excipients
  • Co-administration of terfenadine in patients receiving fluconazole at multiple doses of 400 mg per day or higher
  • Co-administration of other medicinal products known to prolong the QT interval and metabolised via cytochrome P450 (CYP) 3A4, such as cisapride, astemizole, pimozide, quinidine and erythromycin

Side effects

  • Headache (common); somnolence, insomnia, dizziness, paraesthesia, taste perversion and seizures (uncommon)
  • Abdominal pain, vomiting, diarrhoea and nausea (common); constipation, dyspepsia, flatulence and dry mouth (uncommon)
  • Raised alanine aminotransferase, aspartate aminotransferase and blood alkaline phosphatase (common); cholestasis, jaundice and raised bilirubin (uncommon); hepatic failure, hepatocellular necrosis, hepatitis and hepatocellular damage (rare)
  • Rash (common); drug eruption, urticaria, pruritus and increased sweating (uncommon); toxic epidermal necrolysis and drug reaction with eosinophilia and systemic symptoms (DRESS)
  • Torsade de pointes and QT prolongation (rare); anaemia (common), with agranulocytosis, leukopenia, thrombocytopenia and neutropenia (uncommon); anaphylaxis (uncommon)

Interactions

  • Terfenadine — co-administration contraindicated at fluconazole multiple doses of 400 mg/day or higher (§4.3)
  • Cisapride, astemizole, pimozide, quinidine and erythromycin — QT-prolonging CYP3A4-metabolised medicines; co-administration contraindicated (§4.3)
  • Other QT-prolonging medicinal products such as amiodarone — 'The QT prolongation caused by other medicinal products (such as amiodarone) may be amplified via the inhibition of cytochrome P450 (CYP) 3A4' (§4.4)
  • Oral contraceptives — after fluconazole 200 mg daily, mean AUC increases of about 25% for levonorgestrel and about 38% for ethinyl estradiol versus placebo, both statistically significant (US label drug interaction study)
  • NOTE: SPC §4.5 ('The effect of fluconazole on other medicinal products') was NOT retrieved in full in this source bundle — the clinician must verify the complete interaction list before publishing

Clinical monograph

How it works

Inhibits fungal cytochrome P450-dependent 14-alpha-demethylase, blocking conversion of lanosterol to ergosterol and disrupting fungal cell membrane integrity.

Prescribing in practice

  • Dosing in children and neonates differs markedly by age and renal function and must be confirmed against a children's formulary; neonatal clearance is prolonged so dosing intervals are extended.
  • It is a potent enzyme inhibitor (notably CYP2C9 and CYP3A4) and prolongs the QT interval, so review concurrent medicines for interaction and arrhythmia risk.
  • Adjust dosing in renal impairment and monitor liver function with prolonged or higher-dose courses.

Monitoring

Monitor liver function during prolonged therapy and assess renal function, with ECG consideration where additional QT-prolonging factors or drugs are present.

Counselling the patient

  • Tell the team about any other medicines, as fluconazole interacts with many drugs.
  • Report jaundice, dark urine, persistent nausea or rash to a clinician.
  • Complete the full prescribed course even once the child feels better.

Evidence & guidelines

Fluconazole is an established antifungal supported by SPC and paediatric infectious disease guidance for candidal and cryptococcal infection.

Reference: ESCMID Candida Guidelines; BPNG Neonatal Antifungal Guidelines; NICE Preterm Birth Guidance NG25; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.