Fluconazole

See superficial candida infections and invasive candida infections for dosing information

There is limited clinical data about dosing of fluconazole in obese patients. Case reports suggest that higher doses may be required in obese patients who are critically unwell, taking into consideration renal function.

Renal impairment

No dose adjustment in single dose therapy.

For multiple doses, see below:

Hepatic impairment

Use with caution in patients with hepatic impairment and/or when used with other hepatotoxic drugs - monitor LFTs.

Before fluconazole is started see the Summary of Product Characteristics (SPC) for fluconazole for information about interactions, cautions and contraindications.

• Fluconazole is a moderate CYP2C9 and CYP3A4 inhibitor. Fluconazole is also a strong inhibitor of CYP2C19. 
• Co-administration of other medicinal products known to prolong the QT interval and which are metabolised via the cytochrome P450 (CYP) 3A4 (such as cisapride, astemizole, pimozide, quinidine and erythromycin) are contraindicated in patients receiving fluconazole. 
• Co-administration of terfenadine is contra-indicated in patients receiving fluconazole at multiple doses of 400 mg per day or higher based upon results of a multiple dose interaction study

Contraception:

Consider contraception in women of child-bearing potential where the patient is having longer treatment courses of fluconazole. If indicated contraception should be used during treatment period and for 1 week after final dose.

After single dose treatment with fluconazole, a washout period of 1 week (corresponding to 5-6 half-lives) is recommended before becoming pregnant.

Pregnancy: Discuss with pharmacy. Teratogenic in first trimester.

Breastfeeding: Discuss with pharmacy

• Fluconazole should be administered with caution to patients with potentially proarrhythmic conditions.
• LFTs should be monitored during use of fluconazole. The patient should be counselled about hepatic symptoms where they should seek medical advice e.g. jaundice, persistent vomiting or nausea.
• Fluconazole has high oral bioavailability; IV fluconazole should only be used if the patient is NBM or there are concerns over absorption.
• The OUH Antifungal Patient Information Leaflet can be found HERE

1. Aurobindo Pharma - Milpharm Ltd. Summary of Product Characteristics. Fluconazole 150mg capsules [online]. Last revision of the text: 1/3/24. Accessed via: www.emc.medicines.org.uk Accessed 23/3/25

2. ADVANX Pharma. Summary of Product Characteristics. EMC. Fluconazole 2mg/ml Solution for Infusion [online]. Last revision of the text:11/3/24. Accessed via: www.emc.medicines.org.uk Accessed 23/3/25

3. BNF online accessed via www.medicinescomplete.com Accessed 23/3/25

4. Renal Drug Database. Fluconazole. [Internet] Last revision of the text: 11/6/24. Accessed 23/3/25

5. Sanford Guide. Fluconazole. [Internet] Last revision of the text: 3/2/25. Accessed 23/3/25

6. Sanford Guide. Obesity dosing adjustment [Internet] Last updated: December 2024. Accessed 23/3/25

7. UK Teratology Information Service. Use of fluconazole in pregnancy [Internet]. Last updated: November 2024. Accessed 23/3/25

8. LactMed. Fluconazole [Internet] Last updated: October 2024.Accessed 23/3/25