Tadalafil and Enzalutamide: Can They Be Taken Together?
Learn how these medicines interact and what your prescriber checks during your consultation.
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Tadalafil and Enzalutamide: Understanding the Interaction
Published: 20 October 2026
Tadalafil and enzalutamide can be prescribed together, but the interaction requires careful management by your prescriber. Enzalutamide is a medicine used to treat prostate cancer, and it can significantly reduce the effectiveness of tadalafil, a treatment for erectile dysfunction (ED). This page explains how these medicines interact, what your doctor or pharmacist will check, and practical steps to help you get the best outcome from your treatment.
At a glance
What is tadalafil and what is enzalutamide?
Tadalafil is a prescription medicine used to treat erectile dysfunction 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 are sexually aroused [4]. Tadalafil is available as on-demand tablets (usually 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 is the active ingredient in branded Cialis and is also available as a generic medicine.
Enzalutamide is a prescription medicine used to treat prostate cancer. It works by blocking the effects of male hormones (androgens) that can fuel the growth of prostate cancer cells [12]. Enzalutamide is taken as a daily tablet, usually at a dose of 160mg once a day. It is an important treatment for men with advanced or metastatic prostate cancer, and it is often used alongside other cancer therapies.
Many men taking enzalutamide for prostate cancer also experience erectile dysfunction, either as a result of the cancer itself, the treatment, or other health conditions. This is why understanding how tadalafil and enzalutamide interact is important for those seeking ED treatment during cancer therapy.
How do tadalafil and enzalutamide interact?
Enzalutamide is a potent inducer of an enzyme system in the liver called CYP3A4. This enzyme is responsible for breaking down many medicines, including tadalafil [4][12]. When enzalutamide increases the activity of CYP3A4, tadalafil is broken down much more quickly than usual. As a result, the level of tadalafil in your bloodstream may be significantly reduced, and the medicine may not work as well or may not work at all.
In plain English, enzalutamide speeds up the removal of tadalafil from your body, so you may not get the full benefit of the ED treatment. This interaction is well recognised in clinical practice, and your prescriber will take it into account when deciding whether tadalafil is the right option for you, or whether a different approach might be more suitable.
It is important to note that this interaction does not make the combination dangerous in terms of serious side effects or safety concerns. The main issue is reduced effectiveness of tadalafil. Your prescriber may consider adjusting the dose, timing, or even switching to a different treatment if tadalafil does not provide the desired effect while you are taking enzalutamide.
Why does this interaction matter?
If tadalafil is broken down too quickly, you may find that it does not help with erections, or that any improvement is much less than expected. This can be frustrating, especially when ED is already a concern during cancer treatment. Understanding the interaction helps you and your prescriber set realistic expectations and explore alternative options if needed, such as other ED treatments that are not affected by enzalutamide in the same way.
What will your prescriber check before prescribing tadalafil with enzalutamide?
Before prescribing tadalafil to someone taking enzalutamide, your doctor or pharmacist will carry out a thorough review of your current medicines, medical history, and overall health. They will confirm that you are taking enzalutamide and discuss the likelihood that tadalafil may be less effective because of the interaction. They will also check for any other medicines or health conditions that could affect the safety or suitability of tadalafil [2][4].
Your prescriber will ask about your heart health, blood pressure, and any history of stroke, heart attack, or other cardiovascular conditions. Tadalafil can lower blood pressure slightly, and it must not be used with certain medicines such as nitrates (for angina), nicorandil, riociguat, or recreational drugs known as 'poppers'. If you take any of these, do not take tadalafil together with them, as the combination can cause a dangerous drop in blood pressure [4].
Your prescriber will also consider whether other ED treatments might be more suitable. For example, alprostadil (available as a cream or injection) works in a different way and is not affected by enzalutamide. Alternatively, your prescriber may suggest trying tadalafil at a higher dose or more frequent dosing, although this must be done cautiously and only under medical supervision. The goal is to find a treatment that is both safe and effective for you.
What you need to know
- Tadalafil and enzalutamide can be taken together, but enzalutamide may reduce tadalafil's effectiveness.
- Enzalutamide speeds up the breakdown of tadalafil, so the ED treatment may not work as well.
- Your prescriber will review your medicines and may suggest alternatives like alprostadil if tadalafil is not effective.
- Never stop enzalutamide without medical advice, as it is essential for treating prostate cancer.
- Seek urgent help if you have an erection lasting over four hours or sudden vision or hearing loss.
Are there alternatives to tadalafil if enzalutamide reduces its effectiveness?
If tadalafil does not work well because of the interaction with enzalutamide, there are other options to discuss with your prescriber. Other PDE5 inhibitors, such as sildenafil (Viagra), vardenafil (Levitra), and avanafil (Spedra), are also broken down by the CYP3A4 enzyme system, so they may be affected by enzalutamide in a similar way [3][5][6]. However, individual responses can vary, and some men find that one PDE5 inhibitor works better than another, even when taking enzalutamide.
Alprostadil is a prescription treatment that works differently from PDE5 inhibitors. It is available as a cream (Vitaros) applied to the tip of the penis or as an injection (Caverject) into the side of the penis. Because alprostadil does not rely on the CYP3A4 enzyme system, it is not affected by enzalutamide and may be a more reliable option for men taking this cancer treatment [7].
Non-medicine options can also help. Vacuum erection devices (VEDs) are mechanical pumps that draw blood into the penis and can be used alongside or instead of medicines. Psychological support, such as counselling or sex therapy, can be valuable, especially if anxiety or low mood related to cancer treatment is contributing to ED. Your GP, oncologist, or a specialist urology nurse can guide you towards the most appropriate support and treatment for your individual situation.
Can the dose of tadalafil be increased?
In some cases, your prescriber may consider a higher dose of tadalafil to try to overcome the reduced effectiveness caused by enzalutamide. However, this must be done carefully, as higher doses can increase the risk of side effects such as headache, indigestion, back pain, and flushing. Any dose adjustment should only be made by your prescriber after a full review of your response to treatment and your overall health.
Practical advice for taking tadalafil and enzalutamide together
If your prescriber decides that tadalafil is suitable for you while taking enzalutamide, take both medicines exactly as directed. Enzalutamide is usually taken once a day at the same time each day, with or without food. Tadalafil on-demand tablets should be taken at least 30 minutes before sexual activity, and you should not take more than one dose in 24 hours. If you are prescribed daily tadalafil, take it at the same time each day, regardless of when you plan to have sex [4].
Do not stop or change the dose of enzalutamide without speaking to your oncologist, as this medicine is essential for managing your prostate cancer. Similarly, do not take extra tadalafil in the hope of improving its effect, as this will not overcome the interaction and may increase the risk of side effects. If you feel that tadalafil is not working, contact your prescriber to discuss your options rather than adjusting the dose yourself.
Avoid drinking large amounts of alcohol, as this can make erectile dysfunction worse and add to the blood-pressure-lowering effect of tadalafil, leading to dizziness or fainting. Grapefruit juice can also affect the breakdown of tadalafil, so it is best to avoid it while taking this medicine. If you are prescribed any new medicines by another doctor or specialist, always tell them that you are taking both tadalafil and enzalutamide, so they can check for further interactions.
When to get urgent help
- Erection lasting longer than four hours (priapism) – go to A&E or call 999 immediately
- Sudden loss of vision in one or both eyes – seek urgent medical help
- Sudden loss or decrease in hearing, possibly with ringing in the ears or dizziness
- Chest pain during or after sexual activity – stop and seek medical help straight away
- Severe dizziness, fainting, or unexplained shortness of breath while taking these medicines
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
When to seek medical help and warning signs
Most men tolerate tadalafil well, but you should be aware of warning signs that need urgent medical attention. If you develop an erection that lasts longer than four hours (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].
Seek urgent help if you experience sudden loss of vision in one or both eyes, or sudden loss or decrease in hearing, which may be accompanied by ringing in the ears or dizziness. These are rare but serious side effects that require immediate assessment. If you develop chest pain during or after sexual activity, stop and seek medical help straight away, as this could indicate a heart problem [4].
If you notice any new or worsening symptoms while taking tadalafil and enzalutamide together, such as severe dizziness, fainting, or unexplained shortness of breath, contact your GP or oncologist for advice. It is also important to report any side effects from enzalutamide to your cancer care team, as they may need to adjust your treatment plan. Never stop taking enzalutamide without medical advice, as this could affect your cancer treatment.
What if tadalafil stops working over time?
If tadalafil initially helps but then seems to become less effective, this could be due to the ongoing effect of enzalutamide on tadalafil levels, or it could be related to changes in your overall health or cancer treatment. Speak to your prescriber, who can review your treatment and suggest alternatives or adjustments. Do not assume that the medicine has simply 'stopped working' without exploring the reasons and possible solutions.
Tell every doctor about both medicines
Always inform your oncologist, GP, and prescriber that you are taking both enzalutamide and tadalafil. This ensures your treatment is coordinated and safe, and helps your healthcare team find the best solution if tadalafil is not effective.
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 20 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 20 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 20 October 2026]
- Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 20 October 2026]
- Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 20 October 2026]
- Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 20 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 20 October 2026]
- NHS. (n.d.). Erectile dysfunction (impotence). https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ Accessed 20 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 I take tadalafil if I am on enzalutamide for prostate cancer?
Yes, tadalafil can be prescribed alongside enzalutamide, but the cancer treatment may reduce the effectiveness of tadalafil. Your prescriber will discuss whether tadalafil is likely to work for you and explore alternatives if needed.
Will enzalutamide make tadalafil dangerous to take?
No, the interaction between enzalutamide and tadalafil is not dangerous in terms of serious side effects. The main concern is that tadalafil may not work as well because enzalutamide speeds up its breakdown in the body.
Should I stop taking enzalutamide so that tadalafil works better?
No, never stop or change your enzalutamide without speaking to your oncologist. Enzalutamide is essential for treating your prostate cancer, and stopping it could harm your health. Discuss ED treatment options with your prescriber instead.
Are there other ED treatments that work better with enzalutamide?
Alprostadil (cream or injection) is not affected by enzalutamide and may be a more reliable option. Your prescriber can discuss whether alprostadil or other treatments are suitable for you.
Can I take a higher dose of tadalafil to overcome the interaction?
Only if your prescriber advises it. Increasing the dose yourself can lead to side effects and may not overcome the interaction. Always follow your prescriber's instructions.
How long does the interaction between tadalafil and enzalutamide last?
The interaction lasts as long as you are taking enzalutamide. If you stop enzalutamide (only under medical supervision), it may take several weeks for the enzyme-inducing effect to wear off and for tadalafil to work normally again.
Will other PDE5 inhibitors like sildenafil or vardenafil work better with enzalutamide?
Sildenafil, vardenafil, and avanafil are also broken down by the same enzyme system, so they may be affected by enzalutamide in a similar way. However, individual responses vary, and your prescriber can help you find the best option.
Do I need to tell my oncologist that I am taking tadalafil?
Yes, always inform your oncologist and any other doctors treating you about all medicines you are taking, including tadalafil. This helps them manage your overall care and avoid any potential issues.
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Medically reviewed by
Tarun Kumar, Superintendent Pharmacist (GPhC 2233073)