Fluconazole
Class: antifungal – triazole
Indications: fungal infections – cryptococcosis, candidiasis, prophylaxis, dermatomycoses
Contraindications/cautions: renal impairment, hepatic impairment; Susceptibility to QT-interval prolongation
Adverse reactions: common: gastrointestinal upset, nausea, diarrhoea, flatulence, headache less common: rash (discontinue), blood disorders, arrhythmias, dizziness, convulsions, hypokalaemia, taste disturbance
Metabolism/clearance: mainly excreted by the kidneys (fraction excreted by the kidneys unchanged = 0.8) so care in renal failure; halve dose if eGFR less than 50 mL/min/1.73m^2
Interactions:
- increased clinical effect/toxicity of some drugs (see below) (due to increased blood concentrations of them) may occur due to inhibition of metabolising enzymes by fluconazole e.g. diazepam, diclofenac, gliclazide, ibuprofen, indomethacin, lansoprazole, naproxen, omeprazole, pantoprazole, phenytoin, warfarin
- decreased clinical effect of amphotericin may occur with concomitant fluconazole
| Dosing: | ||
|---|---|---|
| oral: | vaginal candidiasis | 150 mg as a single dose |
| cryptococcal infections/systemic candidiasis | 200 to 400 mg once a day for 7 days | |
| oropharyngeal candidiasis | 50 to 100 mg once a day for 7 to 14 days | |
| prophylaxis in malignancy | 50 mg once a day | |
| subcut: | not usually used subcut, iv: refer to package insert | |
| rectal: | not available | |
Syringe driver: not applicable
Mechanism of action: inhibits fungal cell membrane formation
Notes:
- useful in severe or recurrent fungal infections
- may be less likely to interact with other CYP metabolised drugs (see above) than ketoconazole – check QT interactions