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Drug dosage identifier

Fluconazole

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Dose and administration

Intravenous and oral

TREATMENT  12mg/kg/dose  
Age Dosing Interval
<7 days q 72hrs 
7-14 days q 48hrs
>14 days q 24hrs
PROPHYLAXIS  3-6mg/kg/dose  
Age Dosing Interval
<14 days q 72hrs 
14 - 28 days q 48hrs
>28 days q 24hrs

Administer IV dose over 30-120 minutes1

Indications

Treatment of suspected systemic fungal infection and extensive cutaneous and confirmed Candidiasis once sensitivities confirmed.

Contraindications

  1. Co-administration of other drugs which might prolong the QT interval.
  2. Hypersensitivity to fluconazole or related azole compounds. 

Precautions

  1. Administer with caution in patients with liver dysfunction. Discontinue if signs and symptoms of liver disease develop.
  2. Impaired renal or hepatic function. Dose reduction recommended in renal impairment - see "Special Considerations". 

Clinical pharmacology

Fluconazole is a highly selective inhibitor of fungal cytochrome P-450 sterol C-14 α-demethylation, thus inhibiting ergosterol synthesis. Ergosterol is an essential component of the fungal cell membrane, and instability of the cell membrane results in cell death.

It is water-soluble and is well absorbed from the gastrointestinal tract, although it is not generally used via this route in neonates. Oral absorption is unaffected by food intake. It has good CSF penetration and is excreted largely unchanged in urine, therefore dose adjustments are necessary in the presence of impaired renal function. Neonates have a greater volume of distribution and decreased elimination rates compared to older children and adults. The plasma half life in neonates is approximately 70 hours (30 hours in adults). In preterm infants fluconazole was found to have a plasma half life=73 hours (at birth), 53 hours (6 days of age), and 46 hours (at 12 days of age).

Possible interactions

Amphotericin Currently not established if the combination is beneficial or of reduced benefit in terms of antifungal reponse. There is theoretical antagonism seen in vitro but not in vivo.
Caffeine Possible increase in caffeine levels.
Cisapride Increases risk of arrhythmias
Erythromycin Prolongation of QT interval possible
Fentanyl Possible decrease in fentanyl elimination
Chlorothiazide Given orally with oral fluconazole may increase fluconazole levels
Midazolam Increases half-life of midazolam (more likely with higher doses long term)
Theophylline Raises theophylline levels
Phenytoin Raises phenytoin levels - (measure serum levels and reduce phenytoin dose if necessary); possible decrease in fluconazole levels; increase in LFTs
Rifampicin Decreases fluconazole levels, possible increase in LFTs
Zidovudine Increase in zidovudine levels

Possible adverse effects

  1. Hepatic toxicity. Discontinue if signs and symptoms of liver disease develop.
  2. Prolongation of QT interval.
  3. Rash - monitor carefully.
  4. Rarely: leukopenia, thrombocytopenia, toxic epidermal necrolysis, Stevens-Johnson syndrome.
  5. Diarrhoea.

Special considerations

  1. Monitor: Renal & hepatic function Consider reducing dose if there is renal impairment1:
    Mild to moderate renal impairment: give 50% normal dose
    Moderate to severe renal impairment: give 50% of normal dose and extend dosing interval.
  2. Do NOT give by IM or direct IV bolus injection. Continuous infusion is not recommended 4
  3. Systemic Candidiasis is rare without evidence of superficial infection or colonisation.
  4. Not effective against some Candida species (i.e. C.krusei, C.glabrata)
  5. Amphotericin is still the drug of choice for proven Candida infection until sensitivity to Fluconazole is confirmed. However, Fluconazole therapy for established infection can be considered in consultation with the Infectious Diseases service.

Management of IV Fluconazole administration

Description

  • Injection fluconazole 2mg/ml . pH:4 - 8. Osmolality 315 mOsm/L
  • Oral: dry powder for reconstitution to a solution containing fluconazole 50mg/5ml Oral

Prescription

Charted on the prescription chart in mg/dose

Administration

Intravenous

  1. Administer undiluted, through a PALL 0.2 micron filter, over 60 minutes.
  2. Compatible with glucose 5%, glucose 10%, and sodium chloride 0.9%.
  3. Incompatible with frusemide, calcium gluconate. Do NOT mix with other medications.

Oral

Oral doses can be given with food.

Nursing considerations

  1. Monitor ECG, renal function, LFTs, FBC.
  2. Monitor for diarrhoea and feeding intolerance
  3. Monitor for other adverse effects eg. rash

Storage

  1. Injection vials: room temperature, below 30°C.
  2. Reconstituted oral solution: between 5-30°C (preferably in fridge). Note expiry date on label.

References

  1. Phelps SJ, Hak EB, Crill CM, editors. Teddy bear book: Pediatric injectable drugs. 8th ed. Bethesda, MD: American Society of Heath-System Pharmacists; 2007.
  2. Hey, E, editor. Neonatal formulary. 5th ed. Oxford: Blackwell Publishing; 2007
  3. Young TE, Mangum B, editors. Neofax: A manual of drugs used in neonatal care. 18th ed. Raleigh, North Carolina, USA: Acorn Publishing; 2005.
  4. Fluconazole dosing for the prevention or treatment of invasive candidiasis in young infants. Wade KC, Benjamin DK Jr, Kaufman DA, Ward RM, Smith PB, Jayaraman B, Adamson PC, Gastonguay MR, Barrett JS.Pediatr Infect Dis J. 2009 Aug;28(8):717-23

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Document Control

  • Date last published: 30 April 2014
  • Document type: Drug Dosage Guideline
  • Services responsible: ADHB Pharmacy, Neonatology
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years