Introduction Dose reigme Side-effects Drug interactions Drug resistance
Fluconazole is a triazole medicine used to treat fungal infections. It is effective against a broad spectrum of fungi including:
In New Zealand, fluconazole is available as 50 mg, 150 mg and 200 mg capsules on prescription (Diflucan®). There is also a 2 mg/ml injection for intravenous use. In New Zealand, the Pharmaceutical Schedule subsidy of the capsules requires Specialist recommendation except for single-dose use, which is on general prescription and also available over the counter.
Fluconazole binds to the fungal p450 enzymes and stops the cells making ergosterol, the main component of the cell wall.
Fluconazole is well absorbed orally with or without food. It is widely distributed in body tissues. It takes 22 to 30 hours for half of the medication to be cleared from the bloodstream and may take several days of continuous treatment to reach a steady concentration. The drug is eliminated unchanged in the urine so doses should be reduced if there is kidney disease.
For vulvovaginal candidiasis, a single oral dose of fluconazole 150 mg is usually effective. It can be repeated.
For dermatophyte (tinea) infections and pityriasis versicolor, either 50 mg daily or 150 mg once weekly is taken for two to six weeks.
Once-weekly fluconazole is often used off-label to treat toenail fungal infections (onychomycosis).
Larger doses (up to 400 mg daily) are required for systemic infections.
Fluconazole is not normally used in children but doses of 5 mg/kg/day have been safely prescribed for a serious infection.
Fluconazole is generally well tolerated. Occasional side effects include:
Fluconazole should not normally be taken in pregnancy. Use during breast-feeding is acceptable as the drug level found in breast milk is very low.
Unfortunately, fluconazole can interact with other medications.
Fluconazole may increase the concentration of these drugs and enhance their effect:
Rifampicin may slightly decrease the concentration of fluconazole.
Fluconazole is not thought to interact with the oral contraceptive pill.
In recent years, both topical and oral allylamine and triazole antifungal drug resistance has become a problem, particularly in the Indian subcontinent.
Extensive therapy-resistant dermatophyte infection should prompt this as a possible problem. Where available, fungal culture and estimation of drug minimum inhibitory concentration determined to guide appropriate medication.
For more information, see antifungal drug resistance.
Approved datasheets are the official source of information for medicines, including approved uses, doses, and safety information. Check the individual datasheet in your country for information about medicines.
We suggest you refer to your national drug approval agency such as the Australian Therapeutic Goods Administration (TGA), US Food and Drug Administration (FDA), UK Medicines and Healthcare products regulatory agency (MHRA) / emc, and NZ Medsafe, or a national or state-approved formulary eg, the New Zealand Formulary (NZF) and New Zealand Formulary for Children (NZFC) and the British National Formulary (BNF) and British National Formulary for Children (BNFC).
