Tadalafil and Fluconazole: Can You Take Them Together?

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Tadalafil and Fluconazole: Understanding the Interaction

Published: 21 October 2026

If you've been prescribed tadalafil for erectile dysfunction and need fluconazole for a fungal infection, you may wonder whether tadalafil and fluconazole can be taken together safely. The good news is that this combination is not absolutely contraindicated, but fluconazole can increase tadalafil levels in your body, which means your prescriber will need to adjust your dose to keep you safe. Understanding how these medicines interact helps you use both treatments effectively while minimising the risk of side effects.

What is tadalafil and fluconazole used for?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you're sexually aroused [4]. Tadalafil is available as on-demand tablets (10 mg or 20 mg, taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a lower daily dose (2.5 mg or 5 mg) for continuous treatment. It requires sexual stimulation to work and will not cause an erection on its own.

Fluconazole is an antifungal medicine used to treat a range of fungal infections, including thrush (candidiasis), ringworm, and more serious systemic infections. It works by stopping the growth of fungi and is available in different strengths depending on the type and severity of infection. Fluconazole is commonly prescribed as a single 150 mg capsule for genital thrush, but longer courses or higher doses may be needed for other infections. It is generally well tolerated and effective for most fungal conditions.

How do tadalafil and fluconazole interact?

Fluconazole can increase the amount of tadalafil in your bloodstream by slowing down how quickly your body breaks it down. This happens because fluconazole inhibits an enzyme in your liver called CYP3A4, which is responsible for metabolising (breaking down) tadalafil [4]. When this enzyme is blocked, tadalafil stays in your system longer and at higher concentrations, which can increase both its effects and the risk of side effects such as headache, flushing, indigestion, dizziness, or a drop in blood pressure.

The degree of interaction depends on the dose and duration of fluconazole. A single 150 mg dose for thrush causes only a modest increase in tadalafil levels and is usually well tolerated. However, higher doses or longer courses of fluconazole (for example, 200–400 mg daily for several days or weeks) have a stronger effect on CYP3A4 and may require your tadalafil dose to be reduced. Your prescriber will assess your individual situation, including the dose and duration of both medicines, to decide whether any adjustment is needed.

It's important to note that this interaction does not mean you cannot take the two medicines together. Unlike nitrates, nicorandil, riociguat, or poppers—which must never be combined with tadalafil because of the risk of a dangerous drop in blood pressure—fluconazole simply requires careful dose management. Always tell your prescriber or pharmacist about all medicines you are taking, including short courses of antifungals, so they can advise you safely.

What happens if the interaction is not managed?

If you take a normal dose of tadalafil while on fluconazole without dose adjustment, you may experience stronger or longer-lasting side effects. Common side effects of tadalafil include headache, facial flushing, nasal congestion, indigestion, and back pain [4]. These may become more noticeable or bothersome if tadalafil levels are higher than intended. More significantly, the blood-pressure-lowering effect of tadalafil can be enhanced, leading to dizziness, light-headedness, or fainting, especially when standing up quickly. If you experience chest pain during sex, an erection lasting more than four hours, or sudden loss of vision or hearing, seek urgent medical help.

What will my prescriber check before prescribing tadalafil and fluconazole together?

When you request tadalafil through an online consultation at Cured Pharmacy, you'll be asked to list all your current medicines, including any antifungals like fluconazole. A UK-registered prescriber will review your answers to check for interactions and decide whether tadalafil is safe and suitable for you. If you are taking or about to start fluconazole, the prescriber will consider the dose and duration of your antifungal treatment and may recommend starting tadalafil at a lower dose or reducing your usual dose temporarily.

For example, if you are taking a single 150 mg fluconazole capsule for thrush, the prescriber may advise you to use tadalafil 10 mg instead of 20 mg, or to wait a day or two after the fluconazole before taking tadalafil, depending on your individual circumstances. If you are on a longer course of fluconazole at higher doses, the prescriber may recommend a lower maximum dose of tadalafil (for instance, no more than 10 mg in a 72-hour period) to avoid excessive drug levels [4].

The prescriber will also check that you do not have any other conditions or take any other medicines that would make tadalafil unsuitable. This includes checking for use of nitrates, nicorandil, riociguat, or poppers (which are absolute contraindications), as well as alpha-blockers, other blood-pressure medicines, or additional CYP3A4 inhibitors. You should also mention any history of heart problems, stroke, very low blood pressure, liver or kidney disease, or previous sudden vision loss, as these may affect whether tadalafil is safe for you.

Practical advice for taking tadalafil and fluconazole safely

If you have been prescribed both tadalafil and fluconazole, follow your prescriber's instructions carefully regarding dose and timing. Do not take more tadalafil than recommended, and do not take it more often than advised. If you are taking a short course of fluconazole (such as a single capsule for thrush), you may be advised to use a lower dose of tadalafil for a few days or to skip a dose if you have recently taken fluconazole. If you are on a longer course of fluconazole, your prescriber may recommend a reduced maximum dose of tadalafil for the duration of your antifungal treatment.

Avoid drinking grapefruit juice while taking tadalafil, as it can also inhibit CYP3A4 and further increase tadalafil levels. Limit alcohol intake, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effects of tadalafil, increasing the risk of dizziness or fainting. If you feel dizzy or light-headed, sit or lie down until the feeling passes, and avoid driving or operating machinery.

If you develop any new or worsening side effects while taking tadalafil and fluconazole together, contact your prescriber or pharmacist for advice. Do not stop taking a prescribed medicine without consulting a healthcare professional. If you experience chest pain during sex, an erection lasting more than four hours, or sudden loss of vision or hearing, seek urgent medical help immediately.

What if I need fluconazole after starting tadalafil?

If you are already taking tadalafil and your GP or pharmacist prescribes fluconazole for a new infection, let them know you are using tadalafil. They can advise whether you should continue your usual tadalafil dose, reduce it temporarily, or skip doses while on fluconazole. For a single-dose fluconazole treatment, you may simply be advised to use a lower dose of tadalafil for the next few days. Always check with your prescriber or pharmacist rather than making changes on your own.

Other antifungal medicines and tadalafil interactions

Fluconazole is not the only antifungal that can interact with tadalafil. Other azole antifungals, particularly ketoconazole and itraconazole, are even more potent inhibitors of CYP3A4 and can cause a greater increase in tadalafil levels [4]. If you are prescribed ketoconazole or itraconazole, your tadalafil dose will need to be reduced more significantly—often to a maximum of 10 mg in 72 hours—and your prescriber may advise against using tadalafil daily doses altogether. These stronger antifungals are usually reserved for more serious or resistant fungal infections.

Other antifungals, such as clotrimazole or miconazole used as creams, pessaries, or oral gels, are less likely to interact with tadalafil because they are not well absorbed into the bloodstream. However, oral miconazole gel can still have some systemic absorption, so it's worth mentioning to your prescriber. Terbinafine, another commonly used antifungal (often for nail infections), does not significantly inhibit CYP3A4 and is not expected to interact with tadalafil in a clinically meaningful way.

Always tell your prescriber or pharmacist about any antifungal treatment you are using or planning to use, including over-the-counter products. They can check whether an interaction is likely and advise you on safe use. Never assume that because a medicine is available without prescription, it cannot interact with your other treatments.

When to seek medical advice about tadalafil and fluconazole

You should contact your prescriber or pharmacist if you experience any new or troublesome side effects after starting tadalafil and fluconazole together. Common side effects such as headache, flushing, or indigestion may be more noticeable if tadalafil levels are raised, but they are usually mild and temporary. However, if you feel very dizzy, faint, or unwell, or if side effects are severe or persistent, seek advice promptly.

Seek urgent medical help (call 999 or go to A&E) if you experience chest pain during or after sex, as this could be a sign of a heart problem. An erection lasting more than four hours (priapism) is a medical emergency and requires immediate treatment to prevent permanent damage. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are rare but serious side effects that require urgent assessment.

If you have any questions or concerns about taking tadalafil and fluconazole together, or if your circumstances change (for example, you are prescribed a new medicine or your antifungal dose is increased), contact your prescriber or pharmacist for advice. At Cured Pharmacy, our team is here to support you with clear, evidence-based guidance to help you use your medicines safely and effectively.

Can I get tadalafil online if I'm taking fluconazole?

Yes, you can request tadalafil through an online consultation at Cured Pharmacy even if you are taking fluconazole, provided you declare this during your consultation. A UK-registered prescriber will review your medical history and current medicines, including fluconazole, and decide whether tadalafil is safe and appropriate for you. If suitable, they will recommend the correct dose and provide clear instructions on how to take it safely alongside your antifungal treatment. All prescription medicines are only supplied after a clinical assessment to ensure your safety.

Scientific References

1. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 21 October 2026]
2. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 21 October 2026]
3. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 21 October 2026]

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.

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