Tadalafil and Itraconazole: Can They Be Taken Together?
Learn how this antifungal interacts with tadalafil and what dose adjustments keep you safe.
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Tadalafil and Itraconazole: Understanding the Interaction and Safe Use
Published: 22 October 2026
Tadalafil and itraconazole can interact because itraconazole is a potent CYP3A4 inhibitor that raises tadalafil levels in your bloodstream. This interaction is manageable with dose adjustments, but it must be reviewed by your prescriber before you start treatment. Understanding how these medicines work together helps you use tadalafil safely and effectively while taking an antifungal.
Key takeaways
- Itraconazole raises tadalafil levels by blocking the enzyme that breaks it down in your liver.
- Your prescriber will reduce the maximum tadalafil dose to 10mg in 72 hours if you take itraconazole.
- Declare all medicines during your consultation to ensure safe dose adjustments and avoid interactions.
- Seek urgent help for erections lasting over 4 hours, sudden vision or hearing loss, or chest pain.
- Avoid grapefruit juice and limit alcohol while taking tadalafil with itraconazole.
What is tadalafil and what is itraconazole?
Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor used to treat erectile dysfunction (ED). It works by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused [4]. Tadalafil is available as on-demand tablets (10mg or 20mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low-dose tablet (2.5mg or 5mg). It requires sexual stimulation to work and is taken by mouth.
Itraconazole is an antifungal medicine used to treat a range of fungal infections, including nail infections, skin infections, and more serious systemic fungal conditions [12]. It belongs to the azole class of antifungals and works by stopping fungi from making their protective cell walls. Itraconazole is a potent inhibitor of an enzyme in your liver called CYP3A4, which is responsible for breaking down many medicines, including tadalafil. This means itraconazole can significantly increase the levels of tadalafil in your body.
How do tadalafil and itraconazole interact?
The interaction between tadalafil and itraconazole happens in your liver. Tadalafil is normally broken down by an enzyme called CYP3A4. Itraconazole is a potent inhibitor of this enzyme, meaning it slows down or blocks the breakdown of tadalafil [4]. When tadalafil is not broken down as quickly, more of it stays in your bloodstream for longer, and the levels can become higher than intended.
Higher tadalafil levels increase the risk of side effects such as headache, flushing, indigestion, back pain, muscle aches, dizziness, and a drop in blood pressure. The interaction does not make the combination unsafe in all cases, but it does require careful dose adjustment. Your prescriber will reduce the maximum dose of tadalafil you can take while you are on itraconazole to keep the levels within a safe range. This is a well-recognised interaction, and UK prescribers routinely check for it during consultations [12].
Why CYP3A4 matters
CYP3A4 is one of the most important enzymes in your liver for processing medicines. Many commonly prescribed drugs rely on CYP3A4 for their breakdown and elimination from the body. When a potent inhibitor like itraconazole is present, it can affect multiple medicines at once. This is why your prescriber and pharmacist will always ask about all your current medicines, including over-the-counter treatments and supplements, before approving a prescription for tadalafil or any other ED medicine.
At a glance
What dose adjustments are needed for tadalafil and itraconazole?
If you are taking itraconazole, your prescriber will adjust your tadalafil dose to reduce the risk of side effects. For on-demand tadalafil, the maximum recommended dose is usually reduced to 10mg in any 72-hour period [4]. This is lower than the standard maximum of 20mg in 24 hours for people not taking CYP3A4 inhibitors. The lower dose and longer gap between doses help keep tadalafil levels safe.
For daily tadalafil (2.5mg or 5mg), your prescriber may advise against this regimen altogether while you are on itraconazole, or they may reduce the dose further depending on your individual circumstances. The decision will be based on the strength and duration of your itraconazole treatment, your overall health, and any other medicines you take. Never adjust your tadalafil dose yourself; always follow the prescriber's instructions and discuss any concerns during your consultation [12].
What your prescriber checks before approving tadalafil with itraconazole
During your online consultation at Cured Pharmacy, the prescriber will review your full medical history and current medicines. They will check that you are not taking any medicines that are contraindicated with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs known as poppers (amyl or alkyl nitrites). These combinations can cause a dangerous drop in blood pressure and must never be used together [4].
The prescriber will also check for other medicines that can interact with tadalafil, including alpha-blockers (such as doxazosin or tamsulosin), other blood-pressure medicines, and any additional CYP3A4 inhibitors. They will assess your cardiovascular health to ensure that sexual activity is safe for you, particularly if you have a history of heart attack, stroke, unstable angina, or severe heart failure. If you have ever experienced sudden vision loss (a condition called non-arteritic anterior ischaemic optic neuropathy, or NAION) or have certain inherited retinal disorders, tadalafil may not be suitable [2][4].
The prescriber will confirm the dose and duration of your itraconazole treatment. If you are on a short course of itraconazole, they may advise waiting until it is finished before starting tadalafil. If you need long-term antifungal treatment, they will prescribe the adjusted tadalafil dose and provide clear instructions on how to take it safely.
Declaring all your medicines
It is essential to list every medicine you take during your consultation, including prescription medicines, over-the-counter treatments, herbal remedies, and supplements. Some interactions are not immediately obvious, and even seemingly unrelated medicines can affect how tadalafil works or increase the risk of side effects. If you start a new medicine after your tadalafil prescription has been approved, contact your GP or pharmacist to check whether it is safe to continue.
Always declare your antifungal
Tell your prescriber about itraconazole or any other antifungal medicine during your consultation. This ensures your tadalafil dose is adjusted correctly and keeps you safe from avoidable side effects.
Practical advice for taking tadalafil while on itraconazole
If your prescriber approves tadalafil while you are taking itraconazole, follow the dose and timing instructions carefully. Take tadalafil at least 30 minutes before sexual activity if using the on-demand dose, and remember that it requires sexual stimulation to work. Do not take more than the prescribed dose, and do not take it more often than instructed. If you have been prescribed a maximum of 10mg in 72 hours, set a reminder to avoid accidental overlap.
Avoid drinking grapefruit juice while taking tadalafil, as it can also inhibit CYP3A4 and further raise tadalafil levels [4]. 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 experience side effects such as severe headache, dizziness, chest pain, or visual disturbances, stop taking tadalafil and seek medical advice promptly.
If your itraconazole course finishes and you wish to continue using tadalafil, contact your prescriber to discuss whether your dose can be adjusted back to the standard regimen. Do not change your dose without professional advice. Keep both medicines stored safely, away from children, and check the expiry dates regularly.
Warning signs and when to seek urgent help with tadalafil and itraconazole
Most people tolerate tadalafil well, even when taking itraconazole, provided the dose is adjusted correctly. However, you should be aware of warning signs that require urgent medical attention. If you develop an erection that lasts longer than four hours (a condition called priapism), go to A&E immediately or call 999. Priapism is a medical emergency that can cause permanent damage to the penis if not treated quickly [4].
Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (which may be accompanied by ringing in the ears or dizziness), are rare but serious side effects. Stop taking tadalafil and seek urgent medical help if these occur [4]. If you experience chest pain during or after sexual activity, do not use nitrate medicines such as GTN spray to relieve it, as the combination with tadalafil can be dangerous. Call 999 and tell the paramedics or doctor that you have taken tadalafil.
If you develop signs of an allergic reaction—such as swelling of the face, lips, tongue or throat, difficulty breathing, or a severe skin rash—seek emergency help immediately. Less urgent side effects, such as persistent headache, indigestion, or back pain, should be discussed with your GP or pharmacist. Always read the patient information leaflet that comes with your medicine and report any unexpected symptoms.
Reporting side effects
If you experience side effects while taking tadalafil, you can report them via the Yellow Card Scheme at yellowcard.mhra.gov.uk or by searching for the Yellow Card app. Reporting helps the Medicines and Healthcare products Regulatory Agency (MHRA) monitor the safety of medicines. You can also discuss side effects with your GP, pharmacist, or the prescriber who approved your treatment.
When to get urgent help
- Erection lasting longer than 4 hours (priapism) – go to A&E or call 999 immediately
- Sudden loss of vision in one or both eyes – stop tadalafil and seek urgent medical help
- Sudden decrease or loss of hearing, ringing in ears, or dizziness – seek urgent medical advice
- Chest pain during or after sex – call 999 and tell them you have taken tadalafil; do not use GTN spray
- Severe allergic reaction (swelling of face, lips, tongue, throat, difficulty breathing) – call 999
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
Scientific References
- National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 22 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 22 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 22 October 2026]
- Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 22 October 2026]
- Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 22 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 22 October 2026]
- NHS. (n.d.). Erectile dysfunction (impotence). https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ Accessed 22 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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Common Questions
Can't find your answer? Our UK pharmacists review every consultation and can help.
Can I take tadalafil if I'm on a short course of itraconazole?
Your prescriber may advise waiting until the itraconazole course is finished, or they may approve a reduced tadalafil dose with clear instructions. Discuss your treatment plan during your consultation.
Will itraconazole stop tadalafil from working?
No, itraconazole does not reduce tadalafil's effectiveness. It raises tadalafil levels, which is why dose adjustments are needed to avoid side effects.
Can I take the full 20mg tadalafil dose if I'm on itraconazole?
No, the maximum recommended dose is usually 10mg in any 72-hour period when taking itraconazole. Your prescriber will confirm the correct dose for you.
What if I forget I'm taking itraconazole and take tadalafil?
Contact your GP or pharmacist for advice. Monitor for side effects such as severe headache, dizziness, or chest pain, and seek urgent help if these occur.
Are other ED medicines safer than tadalafil with itraconazole?
All PDE5 inhibitors (sildenafil, vardenafil, avanafil) interact with itraconazole. Vardenafil and avanafil are contraindicated or not recommended with potent CYP3A4 inhibitors; tadalafil and sildenafil can be used with dose adjustments.
Can I drink alcohol while taking tadalafil and itraconazole?
Limit alcohol intake, as it can worsen erectile dysfunction and add to the blood-pressure-lowering effects of tadalafil, increasing the risk of dizziness.
How long after stopping itraconazole can I take a normal tadalafil dose?
Itraconazole can stay in your system for several days. Your prescriber will advise when it is safe to return to the standard dose, usually after the antifungal has cleared.
Do I need to tell my GP if I'm taking tadalafil and itraconazole together?
Yes, always inform your GP and any other healthcare professionals about all your medicines, including ED treatments, to ensure safe and coordinated care.
Medically reviewed by
Tarun Kumar, Superintendent Pharmacist (GPhC 2233073)