An azole antifungal medicine
Fluconazole
An oral azole antifungal for thrush and other candida (yeast) infections — available over the counter for vaginal thrush but with several important drug interactions.
What is Fluconazole?
Fluconazole is an azole antifungal taken by mouth to treat yeast (candida) infections, most commonly vaginal thrush, as well as oral thrush and other candida infections. A single dose is often enough for straightforward thrush.
Education and reference only. This is a plain-language guide to Fluconazole — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Fluconazole is an azole antifungal medicine taken by mouth to treat yeast (candida) infections — most commonly vaginal thrush, but also oral thrush and other candida infections. For straightforward vaginal thrush it is widely available over the counter as a single treatment, while longer courses are prescribed for more persistent or more serious fungal infections. It is convenient and effective, but it has a number of important interactions with other medicines. A common brand in the UK and US is Diflucan.
How it works
Fluconazole interferes with the fungal cell membrane. It blocks an enzyme the fungus uses to make ergosterol, an essential building block of the membrane that surrounds each fungal cell. Without enough ergosterol the membrane becomes leaky and the fungus cannot grow or survive, so the infection clears. Because the enzyme it blocks is similar to ones the human liver uses to process certain medicines, fluconazole can also slow the breakdown of some other drugs — which is the source of many of its interactions.
Company & origin
Originated / developed by: Pfizer.
Fluconazole was discovered by Pfizer scientists (including Kenneth Richardson) at the company's Sandwich, UK research site, with the compound emerging around 1981 and approved in the US in 1990 as the triazole antifungal Diflucan.
Practical use
How to take Fluconazole
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is swallowed and can be taken with or without food.
- Straightforward vaginal thrush is often treated with a single dose, while other infections may need a longer course as prescribed.
- Tell your doctor or pharmacist about your other medicines, as fluconazole interacts with several, including warfarin and some statins.
- Avoid it in pregnancy unless your clinician advises otherwise.
- See a doctor if thrush keeps coming back or does not clear, as further assessment may be needed.
- Report any rash, yellowing of the skin or eyes, or signs of a serious reaction.
Weighing it up
Advantages & disadvantages of Fluconazole
Advantages
- Convenient oral treatment, often a single dose for thrush.
- Effective against common yeast infections.
- Can treat infections that topical preparations cannot reach.
- Available without prescription for uncomplicated vaginal thrush.
Disadvantages
- Interacts with a number of other medicines.
- Can cause nausea, stomach upset, headache or rash.
- Generally avoided in pregnancy.
- Rarely affects the liver or heart rhythm and is not for recurrent thrush without review.
Practical use
Good to know
For simple vaginal thrush, fluconazole is often a single over-the-counter treatment; oral thrush and other infections may need longer prescribed courses. Its most important practical issue is interactions — it can raise the levels and effects of medicines such as some statins and warfarin (where it can push the INR up and raise bleeding risk), among others, so it is important to mention everything you take, including the contraceptive pill. Like some antifungals it can occasionally affect the heart's rhythm (QT prolongation). It is generally avoided in pregnancy, and people with liver problems are treated cautiously.
Who should not take it / use with caution
- Women who are pregnant or planning pregnancy — fluconazole is generally avoided, and a local antifungal is usually preferred instead.
- People taking certain medicines that should not be combined with it (see interactions), or with certain heart-rhythm risks (such as QT prolongation).
- Used with caution in significant liver disease and in those with low blood potassium or magnesium.
Monitoring
- Response of the infection
- Liver function in longer courses or liver disease
- INR if taken with warfarin
Side effects
- Nausea, tummy upset, diarrhoea or headache are the most common effects.
- Skin rash, and occasionally changes in liver blood tests.
- Rarely, serious liver problems, serious skin reactions, or heart-rhythm changes (QT prolongation) — seek advice if you notice yellowing of the skin or eyes, a spreading rash, or feeling very unwell.
Key interactions
- It can raise the levels and effects of several medicines, including some statins (raising muscle-injury risk) and warfarin (raising the INR and bleeding risk).
- Care is needed with medicines that affect heart rhythm (QT prolongation) and with certain other drugs whose levels it can increase.
- It can affect some diabetes medicines and a number of others — always check your full medicine list with a pharmacist before taking it.
Available as: Capsules, tablets, a liquid (suspension), and a form given by drip in hospital. The single capsule for vaginal thrush is available over the counter from pharmacies.
Answers
Fluconazole: frequently asked questions
Can I buy fluconazole without a prescription?
For straightforward vaginal thrush, a single fluconazole capsule is available over the counter from pharmacies. Longer courses for oral thrush or other fungal infections, and treatment for anyone the pharmacy cannot supply (for example in pregnancy or with certain other medicines), need a prescription.
Why does it interact with so many medicines?
Fluconazole slows down some of the liver enzymes that the body uses to break down other medicines, so it can raise the levels of drugs such as some statins and warfarin. This is why it is important to tell your pharmacist or prescriber everything you take before starting it.
Can I take it if I am pregnant?
Oral fluconazole is generally avoided in pregnancy, and a local antifungal treatment (such as a pessary or cream) is usually preferred for thrush. If you are or might be pregnant, tell the pharmacist or prescriber so a safe alternative can be chosen.
Why has my thrush come back after treatment?
Thrush can recur, sometimes because of an underlying trigger such as recent antibiotics, diabetes or a weakened immune system, or because a longer course is needed. If it keeps returning, see a pharmacist or GP rather than repeatedly self-treating, so the cause can be looked into.
What is the difference between fluconazole and Diflucan?
They are the same medicine — fluconazole is the generic (active-ingredient) name and Diflucan is a brand name. Generic fluconazole contains the identical active ingredient.
The wider class
About Azole antifungals
Fluconazole belongs to the azole antifungals class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
Browse by body system
Authoritative sources
- BNF: Fluconazole.
- electronic Medicines Compendium (SmPC): Fluconazole (Diflucan).
- NICE CKS: Fluconazole.
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.