Fluconazole is an antifungal medicine, not an antibiotic. It treats fungal infections caused mainly by Candida — vaginal thrush, oral thrush, some skin and nail infections, and serious fungal infections including cryptococcal meningitis. A single 150 mg dose is the usual treatment for uncomplicated vaginal thrush.

What is Fluconazole?

Fluconazole is a triazole antifungal. This distinction matters more than any other on this page: it treats fungal infections, not bacterial ones. Antibiotics such as amoxicillin have no effect on fungi, and fluconazole has no effect on bacteria.

It works by blocking an enzyme fungi need to make ergosterol, a component of their cell membrane. Without it the membrane becomes leaky and the fungal cell fails. Human cells use cholesterol rather than ergosterol, which is why the medicine targets fungi specifically.

Fluconazole is well absorbed when taken by mouth and reaches most parts of the body, including the fluid around the brain and spinal cord — which is why it has a role in serious systemic infections as well as everyday thrush.

In South Africa it is dispensed as capsules and tablets, commonly 50 mg, 150 mg and 200 mg, as a suspension and as an infusion. Depending on the strength and pack, it may be available as a Schedule 3 pharmacy medicine or on prescription.

What is Fluconazole commonly used for?

Fluconazole is prescribed for fungal infections including:

Vaginal thrush (vaginal candidiasis). A single 150 mg dose is the usual treatment for an uncomplicated episode. Recurrent thrush may need a longer course.
Oral thrush, including in denture wearers, inhaled-steroid users and people with weakened immunity.
Oesophageal candidiasis, where thrush extends into the gullet.
Skin fungal infections, where topical treatment has not worked or the area is extensive.
Fungal nail infections, though these need long treatment and other medicines are often preferred.
Cryptococcal meningitis, both as treatment and as long-term prevention. This is a significant use in South Africa, where cryptococcal disease is an important opportunistic infection in advanced HIV.
Preventing fungal infection in people with severely weakened immunity.

Men get thrush too, which is behind a common search around this medicine. Candidal balanitis causes irritation, redness and soreness of the penis, and fluconazole is a recognised treatment. It is not solely a women’s medicine, and partners sometimes need treating together.

How Fluconazole fits into this medicine category

Fluconazole is an antifungal, which puts it in a different part of this category from everything antibacterial:

Antibacterials — penicillins, macrolides, quinolones, nitroimidazoles — treat bacterial infections.
Antifungals — fluconazole, clotrimazole, miconazole, terbinafine, nystatin — treat fungal infections.
Antiparasitics — including metronidazole for some organisms — treat parasitic infections.

There is a practical connection worth knowing: antibiotics often cause thrush. By disturbing the normal balance of bacteria, a course of amoxicillin can let yeast overgrow. That is why thrush after antibiotics is common, and why fluconazole and an antibiotic are sometimes needed in sequence rather than because one failed.

Within antifungals, the choice between oral fluconazole and a topical treatment such as clotrimazole depends on the site, severity and whether topical treatment is practical. See the antibiotics, antifungals and antimicrobials hub.

What to check before using Fluconazole

Be reasonably sure it is thrush. Vaginal symptoms overlap considerably between thrush, bacterial vaginosis and trichomoniasis, and they need different treatments — an antifungal will not touch the latter two. If this is a first episode, if symptoms are unusual, or if treatment has not worked before, get it checked rather than self-treating.

Tell your prescriber or pharmacist if:

You are pregnant, planning pregnancy or breastfeeding. Oral fluconazole is generally avoided in pregnancy, particularly at higher amounts, and topical treatment is usually preferred. This matters and is worth raising explicitly.
You have liver disease.
You have a heart rhythm condition, or a family history of sudden cardiac death. Fluconazole can prolong the QT interval.
You have kidney disease.
You take warfarin — fluconazole increases its effect and bleeding risk.
You take a statin, particularly simvastatin, which raises the risk of muscle problems.
You take medicines for diabetes, epilepsy, HIV, or immune suppression, or amitriptyline, quetiapine or methadone.

Fluconazole interacts with a wide range of medicines because of how the liver processes it. Give your pharmacist a full list.

Possible cautions and when to ask a pharmacist or doctor

Interactions are the main practical caution. The list above is not exhaustive. A single 150 mg dose for thrush is far less likely to cause problems than a longer course, but the warfarin and statin interactions matter even then.

Expect possible nausea, headache or abdominal discomfort. These are usually mild.

Report yellowing of the eyes or skin, dark urine, persistent nausea or unusual tiredness — these can indicate liver problems and need prompt assessment.

A rash needs attention. Serious skin reactions are rare but have been reported; a spreading rash, blistering, or involvement of the mouth or eyes needs urgent medical attention.

If thrush does not clear, do not simply repeat the dose indefinitely. Recurrent or resistant thrush needs assessment — sometimes the diagnosis is different, sometimes an underlying cause such as diabetes or immune suppression is involved.

Recurrent thrush is a reason to see a doctor, particularly four or more episodes a year, or thrush alongside unexplained weight loss or other symptoms.

Seek medical attention for severe abdominal pain, signs of liver problems, a spreading rash, palpitations or fainting.

Related medicine guides

Frequently asked questions

What is fluconazole 150 mg used for? Most commonly a single dose for uncomplicated vaginal thrush. Other strengths and longer courses are used for oral thrush, skin infections and serious fungal infections.

Is fluconazole an antibiotic? No. It is an antifungal. Antibiotics treat bacteria and have no effect on fungi; fluconazole is the reverse.

Can men take fluconazole? Yes. Men get candidal infections too, and fluconazole is a recognised treatment for candidal balanitis.

Is it safe in pregnancy? Oral fluconazole is generally avoided during pregnancy, particularly at higher amounts. Topical treatment is usually preferred. Speak to your doctor or pharmacist.

Why do I keep getting thrush after antibiotics? Antibiotics disturb the normal bacterial balance, letting yeast overgrow. It is common, and treatable.

My thrush has not cleared after one dose. What now? See a pharmacist or doctor rather than repeating indefinitely. The diagnosis may be different, or there may be an underlying cause worth investigating.

What Is Fluconazole Used For?