Fluconazole

Fungal infections including vaginal thrush, oral thrush, and certain skin and systemic fungal conditions are common and can cause significant discomfort. Fluconazole tablets are an antifungal medication belonging to the triazole class, used in adults and children to treat a wide range of fungal infections caused by Candida and Cryptococcus species. Whether you need oral candidiasis relief, yeast infection therapy, or treatment for a systemic fungal condition, fluconazole is available in three strengths: 50 mg, 150 mg, and 200 mg. The 200 mg and 50 mg strengths require a prescription; the 150 mg single capsule for vaginal thrush is available as a Pharmacy Medicine following pharmacist assessment.

PRESCRIPTION ONLY MEDICINE (POM): Fluconazole 50 mg and 200 mg are Prescription Only Medicines (POM). They can only be supplied following a clinical consultation and the issuing of a valid prescription by a registered prescriber. Fluconazole 150 mg is available as a Pharmacy Medicine (P) for vaginal thrush in women aged 16 to 60, following pharmacist assessment without a prescription.

Fluconazole is an oral antifungal medicine belonging to the triazole class. It is available as tablets and capsules in three strengths: 50 mg, 150 mg, and 200 mg. It is also available as an oral suspension and as an intravenous formulation for hospital use. This page covers the oral tablet and capsule formulations only.

Fluconazole has a broad range of licensed indications in the UK. These include: vaginal candidiasis (vaginal thrush) and vaginal candidosis; oropharyngeal candidiasis (oral thrush); oesophageal candidiasis; urinary tract infections caused by Candida; peritonitis caused by Candida; pulmonary infections caused by Candida or Cryptococcus; cryptococcal meningitis; prevention of fungal infections in immunocompromised patients; tinea infections (ringworm and related skin infections); and onychomycosis (fungal nail infections).

Fluconazole is available as a generic medicine from multiple manufacturers and also as the originator brand Diflucan (Pfizer). All contain the same active ingredient at equivalent doses.

Fluconazole kills or inhibits the growth of fungi by disrupting their cell membrane.

Ergosterol Synthesis Inhibition

Fungal cells require ergosterol as the primary sterol in their cell membrane, in the same way that human cells require cholesterol. Ergosterol maintains cell membrane integrity and regulates membrane permeability and fluidity. Fluconazole inhibits the fungal enzyme CYP51 (lanosterol 14-alpha-demethylase), which is responsible for a key step in ergosterol biosynthesis. By blocking this enzyme, fluconazole prevents fungi from producing functional ergosterol, leading to the accumulation of abnormal sterols in the cell membrane.

Fungistatic and Fungicidal Action

The disruption of ergosterol synthesis causes the fungal cell membrane to become abnormally permeable and dysfunctional. Fluconazole acts as a fungistatic agent (inhibiting fungal growth) at lower concentrations and may be fungicidal (killing fungi) at higher concentrations. Effective Candida control through this mechanism supports resolution of both superficial and systemic fungal infection management.

Because the target enzyme, CYP51, is specific to fungi and not present in human cells, fluconazole has selective toxicity against fungi while being relatively well tolerated by the human body. However, fluconazole does inhibit some human cytochrome P450 enzymes, particularly CYP2C9, CYP2C19, and CYP3A4, which underlies its significant drug interaction profile.

Always take fluconazole exactly as your prescriber or pharmacist instructs. The information below summarises key points from the current UK SmPC. The dose, duration, and frequency of treatment vary significantly depending on the indication being treated.

• Fluconazole tablets and capsules can be taken with or without food.
• Swallow the tablet or capsule whole with a glass of water.
• For vaginal thrush (150 mg single dose): take one 150 mg capsule as a single dose. No repeat dose is needed for uncomplicated vaginal thrush.
• For oral thrush (50 mg once daily for 7 to 14 days): your prescriber will specify the duration based on your clinical response.
• For other indications: doses range from 50 mg to 400 mg per day depending on the type and severity of infection. Duration ranges from a single dose to several months for prophylaxis in immunocompromised patients. Always follow your prescriber's specific instructions.
• If you miss a dose, take it as soon as you remember. If your next scheduled dose is close, skip the missed dose and continue as normal. Do not take two doses at once.
• Do not stop taking fluconazole before the prescribed course is complete, unless your prescriber advises otherwise, even if your symptoms improve.
• Some indications require kidney function monitoring, particularly in patients with existing kidney impairment. Fluconazole is primarily excreted by the kidneys, and the dose must be adjusted in patients with reduced kidney function. Your prescriber will assess this before prescribing.

Fluconazole 50 mg Tablets (POM)

The 50 mg strength is a Prescription Only Medicine. It is used for oral and oesophageal candidiasis, urinary tract candidiasis, and superficial skin infections such as tinea pedis, tinea corporis, tinea cruris, and tinea versicolor, typically at 50 mg once daily for between 2 and 6 weeks depending on the indication and clinical response. It is also used for fungal nail infection (onychomycosis) at 50 mg once daily for up to 12 months. All doses and durations are determined by the prescriber.

Fluconazole 150 mg Capsule (P for vaginal thrush; POM for other indications)

The 150 mg single capsule is the standard dose for uncomplicated vaginal candidiasis (vaginal thrush). As a Pharmacy Medicine, it can be obtained from a pharmacist without a prescription, subject to assessment confirming: the symptoms match the patient's previously diagnosed vaginal thrush; the patient is a woman aged 16 to 60; there are no contraindications; and no prescription-only medicines are being taken that interact with fluconazole. For other indications, fluconazole 150 mg requires a prescription.

Fluconazole 200 mg Tablets (POM)

The 200 mg strength is a Prescription Only Medicine used for more serious or systemic fungal infections. These include cryptococcal meningitis (typically 400 mg on day one then 200 to 400 mg daily for 6 to 8 weeks), invasive candidiasis, and antifungal prophylaxis in immunocompromised patients. The 200 mg strength may also be used for tinea infections that have not responded to lower doses, and for onychomycosis at higher doses. All dose regimens are determined by the prescriber and in many cases by a specialist.

Like all medicines, fluconazole can cause side effects. The information below is based on the current UK SmPC. Refer to the Patient Information Leaflet for the full list.

Common Side Effects (may affect up to 1 in 10 people)

• Headache.
• Nausea, abdominal pain, diarrhoea, and indigestion.
• Rash.

Uncommon Side Effects (may affect up to 1 in 100 people)

• Raised liver enzymes on blood tests.
• Dizziness.
• Taste disturbance.
• Flatulence.

Serious Side Effects: Seek Urgent Medical Attention

Go to your nearest accident and emergency department or call 999 immediately if you experience:

• Signs of a serious liver reaction: yellowing of the skin or whites of the eyes, dark urine, severe abdominal pain, or unusual tiredness. Rare but serious liver toxicity including hepatic necrosis has been reported with fluconazole.
• Signs of a serious skin reaction such as widespread blistering, peeling skin, sores inside the mouth, or a severe widespread rash. Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported rarely.
• Signs of a serious allergic reaction including sudden swelling of the face, lips, tongue, or throat, or difficulty breathing.
• Irregular or rapid heart rhythm. Fluconazole can prolong the QT interval on the ECG, which in rare cases can cause serious cardiac arrhythmias. This risk is increased in patients with certain heart conditions and in those taking medicines that also prolong the QT interval.

Report any suspected side effect to your prescriber, pharmacist, or via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Fluconazole May Be Suitable If You:

• Are an adult or child with a confirmed or clinically suspected fungal infection within the licensed indications covered by the relevant strength.
• Have vaginal thrush that has been previously diagnosed by a healthcare provider and matches your current symptoms (for 150 mg Pharmacy Medicine access).
• Do not have contraindications listed below and have informed your prescriber of all current medicines.

Fluconazole Is Not Suitable or Requires Extra Care If You:

• Are pregnant. Fluconazole is teratogenic in animal studies at high doses. A single 150 mg dose for vaginal thrush carries a lower risk, but is generally avoided in pregnancy unless the benefits clearly outweigh the risks. Repeated or high-dose fluconazole is contraindicated in pregnancy. Contact your prescriber before using fluconazole if you are pregnant or may be pregnant.
• Are taking certain medicines that are contraindicated with fluconazole, including: terfenadine, cisapride, astemizole, pimozide, quinidine, and erythromycin — these combinations significantly increase the risk of serious cardiac arrhythmias including QT prolongation and torsade de pointes.
• Are taking warfarin. Fluconazole significantly potentiates the anticoagulant effect of warfarin through CYP2C9 inhibition. INR must be monitored closely and the warfarin dose will typically need to be reduced.
• Are taking phenytoin, ciclosporin, or tacrolimus. Fluconazole increases blood levels of all three through CYP2C9 and CYP3A4 inhibition. Dose adjustment and close monitoring are required.
• Have known liver disease or significantly impaired liver function.
• Have kidney impairment. Dose adjustment is required. The prescriber will assess kidney function before prescribing.
• Have a known allergy or hypersensitivity to fluconazole, other azole antifungals, or any excipient listed in the SmPC.

Fluconazole is a potent inhibitor of CYP2C9 and a moderate inhibitor of CYP2C19 and CYP3A4. This gives it a wide-ranging interaction profile affecting many commonly used medicines. Always tell your prescriber about every medicine you take. Key interactions include:

• Warfarin: fluconazole significantly increases warfarin effect via CYP2C9 inhibition. INR monitoring and warfarin dose reduction are required.
• Statins metabolised by CYP3A4 (simvastatin, atorvastatin, lovastatin): fluconazole increases statin blood levels, raising myopathy risk. For pravastatin, which is not CYP metabolised, the interaction is less significant.
• Oral antidiabetic medicines (sulphonylureas such as glibenclamide, glipizide): fluconazole increases their blood levels via CYP2C9, increasing the risk of hypoglycaemia. Blood glucose monitoring is required.
• Phenytoin: fluconazole increases phenytoin blood levels. Phenytoin levels and toxicity must be monitored.
• Ciclosporin and tacrolimus: fluconazole increases blood levels of both immunosuppressants. Level monitoring and dose adjustment are needed.
• Rifampicin: reduces fluconazole blood levels through enzyme induction, potentially reducing antifungal efficacy.
• QT-prolonging medicines (such as amiodarone, sotalol, and certain antipsychotics): combined use with fluconazole increases the risk of serious cardiac arrhythmias.

Your prescriber will review all current medicines before any prescription is issued.

For fluconazole 50 mg and 200 mg, this medicine is a Prescription Only Medicine. The clinical consultation is the essential first step. A prescription will only be issued if a registered prescriber concludes, based on their individual assessment, that fluconazole is clinically appropriate for you.

During your online consultation with Pharmacy Planet, a registered prescriber will review your symptoms, previous diagnosis, current medicines, liver and kidney function where relevant, and relevant medical history. Given fluconazole's wide-ranging interaction profile, the prescriber will pay particular attention to your complete medicines list.

For fluconazole 150 mg as a Pharmacy Medicine for vaginal thrush, a pharmacist assessment is required. The pharmacist will confirm the diagnosis matches your symptoms, that you are a woman aged 16 to 60, that this is not your first episode or that the symptoms match a previously confirmed diagnosis, and that there are no contraindications or drug interactions.

Not all consultations will result in a prescription. The prescriber may recommend a topical antifungal first or request further clinical information for complex or recurrent infections. This process is designed to protect your safety.

Store below 30°C. Store in the original packaging to protect from moisture. Keep out of the sight and reach of children. Do not use after the expiry date printed on the packaging. Do not dispose of medicines via household waste or wastewater. Return unused or out of date tablets or capsules to your pharmacist for safe disposal. Full storage instructions are provided in the Patient Information Leaflet supplied with your medicine.

Pharmacy Planet is a GPhC-registered online pharmacy providing access to prescription medicines through a clinically led consultation process. Our registered prescribers and pharmacists are committed to patient safety, clinical accuracy, and responsible prescribing. We follow GPhC standards, MHRA guidance, and ASA advertising regulations in all aspects of our service. For medicines with wide-ranging interaction profiles such as fluconazole, our prescribers review all current medicines before any prescription is issued. Every prescription is reviewed and dispensed by qualified healthcare professionals.

If you have questions about fluconazole or any other medicine, our pharmacy team is available to help. We are committed to transparent, patient centred care.

References

1. Electronic Medicines Compendium (eMC). Fluconazole 50 mg, 150 mg and 200 mg tablets/capsules — Summary of Product Characteristics. https://www.medicines.org.uk/emc. Accessed May 2026.
2. NHS. Fluconazole. https://www.nhs.uk/medicines/fluconazole. Accessed May 2026.
3. NHS. Thrush in men and women. https://www.nhs.uk/conditions/thrush-in-men-and-women. Accessed May 2026.
4. Joint Formulary Committee. British National Formulary (BNF). Fluconazole. BMJ Group and Pharmaceutical Press. https://bnf.nice.org.uk. Accessed May 2026.
5. Medicines and Healthcare products Regulatory Agency (MHRA). Yellow Card — report a side effect. https://yellowcard.mhra.gov.uk. Accessed May 2026.