Tadalafil and Abiraterone: Can They Be Taken Together?

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Key takeaways

• Tadalafil and abiraterone can often be taken together, but your prescriber will reduce the tadalafil dose.
• Abiraterone raises tadalafil levels by inhibiting the CYP3A4 enzyme, increasing the risk of side effects.
• Maximum on-demand tadalafil dose is usually 10 mg in 72 hours when taking abiraterone.
• Never take tadalafil with nitrates, nicorandil, riociguat, or poppers—this can cause dangerous low blood pressure.
• Every prescription at Cured Pharmacy follows a clinical consultation reviewed by a UK-registered prescriber.

What Is Tadalafil and What Is Abiraterone?

Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK to treat erectile dysfunction (ED) [3][4]. It works by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Tadalafil is available as on-demand tablets (usually 10 mg or 20 mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low-dose tablet (2.5 mg or 5 mg) [4]. It requires sexual stimulation to work and does not cause an automatic erection.

Abiraterone (often prescribed as abiraterone acetate, brand name Zytiga) is a hormonal cancer medicine used to treat advanced prostate cancer [12]. It works by blocking an enzyme called CYP17A1, which reduces the production of androgens (male hormones) that fuel prostate cancer growth. Abiraterone is taken once daily, usually alongside a corticosteroid such as prednisolone. Because prostate cancer and its treatments can contribute to erectile dysfunction, many men on abiraterone also seek help for ED [1][2].

How Do Tadalafil and Abiraterone Interact?

Abiraterone is a moderate inhibitor of an enzyme called CYP3A4, which is responsible for breaking down tadalafil in the liver [4][12]. When abiraterone slows this breakdown, tadalafil stays in your bloodstream for longer and at higher levels than usual. This means the effects of tadalafil—including its blood-pressure-lowering action—may be stronger or last longer, raising the risk of side effects such as headache, flushing, dizziness, or a drop in blood pressure.

The interaction is not an absolute contraindication (you are not forbidden from taking them together), but it does require dose adjustment and clinical oversight [4]. Your prescriber will typically start you on a lower dose of tadalafil or reduce the maximum dose you can take. For example, if you are on abiraterone, the maximum recommended dose of tadalafil for on-demand use is usually 10 mg in any 72-hour period, rather than the standard 20 mg [4][12]. Always follow the dose your prescriber has given you and never increase it without their advice.

Why CYP3A4 Matters

CYP3A4 is one of the liver's main drug-processing enzymes. Many medicines are metabolised (broken down) by CYP3A4, so when a drug like abiraterone inhibits this enzyme, it can affect the levels of other medicines you take [4][12]. This is why your prescriber and pharmacist will review all your current medicines during your consultation, not just abiraterone. Other CYP3A4 inhibitors include certain antifungals (ketoconazole, itraconazole), some antibiotics (clarithromycin), and HIV medicines (ritonavir, cobicistat), all of which require similar caution with tadalafil [4].

What Your Prescriber Will Check Before Prescribing Tadalafil and Abiraterone Together

Before approving tadalafil for you, your prescriber (doctor or independent pharmacist prescriber) will carry out a thorough clinical assessment [2]. They will ask about your full medication list, including abiraterone, any corticosteroids, and other prescription or over-the-counter medicines. They will also check your blood pressure, cardiovascular history, and whether you have any conditions that make PDE5 inhibitors unsuitable, such as recent heart attack or stroke, unstable angina, severe heart failure, very low blood pressure, or a history of sudden vision loss (non-arteritic anterior ischaemic optic neuropathy, or NAION) [3][4].

Your prescriber will confirm that you are not taking any medicines that must never be combined with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' (amyl or alkyl nitrites) [3][4]. These combinations can cause a dangerous drop in blood pressure. If you are on an alpha-blocker for prostate symptoms (such as tamsulosin or doxazosin), your prescriber will ensure you are stable on that medicine and will start tadalafil at the lowest dose to minimise the risk of dizziness or fainting [4].

Because abiraterone is a CYP3A4 inhibitor, your prescriber will adjust your tadalafil dose accordingly. They may also discuss the timing of doses and advise you to report any new or worsening side effects promptly. At Cured Pharmacy, every prescription for tadalafil follows an online consultation reviewed by a UK-registered prescriber, ensuring your treatment plan is safe and tailored to your individual circumstances.

Practical Advice for Taking Tadalafil and Abiraterone Safely

If your prescriber has approved tadalafil while you are on abiraterone, follow the prescribed dose exactly and do not take more than recommended [4]. For on-demand tadalafil, the usual maximum is 10 mg in any 72-hour period when you are taking a CYP3A4 inhibitor like abiraterone; do not exceed this limit [4][12]. If you have been prescribed daily tadalafil, your prescriber will choose the appropriate low dose (typically 2.5 mg) and monitor you for side effects.

Take abiraterone on an empty stomach (at least one hour before food or two hours after food) as directed, and take tadalafil as instructed—on-demand tablets at least 30 minutes before sexual activity, or daily tablets at the same time each day [4][12]. Avoid drinking grapefruit juice, as it can further raise tadalafil levels and increase the risk of side effects [4]. Limit alcohol intake, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effect of tadalafil [3][4].

Be alert for side effects such as headache, flushing, indigestion, nasal congestion, dizziness, or visual disturbances (such as a blue tinge to vision or increased sensitivity to light) [4]. These are usually mild, but if they are severe or persistent, contact your prescriber. If you experience chest pain during sex, do not use nitrate medicines (GTN spray); stop sexual activity, sit or lie down, and seek urgent medical help [3][4]. If you develop an erection lasting more than four hours (priapism), sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing, go to A&E or call 999 immediately [3][4].

Monitoring and Follow-Up

Your oncologist or GP will monitor your prostate cancer treatment and overall health, including blood pressure and liver function, while you are on abiraterone [12]. Keep all your healthcare providers informed that you are taking tadalafil, and report any new symptoms or concerns. If your abiraterone dose changes or is stopped, or if you start any new medicines, tell your prescriber, as your tadalafil dose may need to be reviewed. Regular follow-up ensures that both medicines continue to work safely and effectively for you.

Are There Alternatives to Tadalafil for Men on Abiraterone?

Tadalafil is not the only option for erectile dysfunction, and your prescriber can discuss alternatives if tadalafil is not suitable or if you prefer a different medicine [2][3]. Other PDE5 inhibitors licensed in the UK include sildenafil (Viagra), vardenafil (Levitra), and avanafil (Spedra) [3][5][6]. All of these are also affected by CYP3A4 inhibitors, so dose adjustments or cautions apply with abiraterone. For example, sildenafil requires a lower starting dose, and vardenafil and avanafil may be contraindicated or require significant dose reduction with potent CYP3A4 inhibitors [3][5][6][12].

Your prescriber will choose the most appropriate PDE5 inhibitor based on your medical history, other medicines, and personal preference (for example, some men prefer the longer duration of tadalafil, while others prefer the faster onset of avanafil) [2][6]. Non-tablet options are also available: Eroxon is a topical gel medical device that can be purchased without prescription, and Vitaros (alprostadil cream) or Caverject (alprostadil injection) are prescription-only alternatives that work differently from PDE5 inhibitors and are not affected by CYP3A4 interactions [7].

If erectile dysfunction persists despite treatment, or if you have concerns about your prostate cancer or its treatment, speak to your oncologist or GP. Erectile dysfunction can sometimes be improved by managing underlying conditions such as diabetes or high blood pressure, reducing stress, or addressing relationship issues [1][2]. Psychological support or psychosexual therapy may also be helpful and can be accessed via your GP [2].

Getting Tadalafil and Abiraterone: What to Expect at Cured Pharmacy

Abiraterone is a specialist cancer medicine usually prescribed and supplied by your hospital oncology team or specialist pharmacy, not by a community pharmacy [12]. Tadalafil, on the other hand, is widely available on prescription for erectile dysfunction. At Cured Pharmacy, a GPhC-registered online pharmacy (GPhC 9012511), you can request tadalafil through a confidential online consultation. A UK-registered prescriber will review your answers, including your current use of abiraterone and any other medicines, and will approve tadalafil only if it is safe and appropriate for you.

We stock a range of tadalafil products, including generic tadalafil tablets and branded Cialis, at transparent prices. For example, generic tadalafil starts at £7.95 for a pack (or £6.36 for your first order with code Ednew), and Tadalafil 20 mg (Teva) is £9.99 (£7.99 with code Ednew). Your medicine is dispensed by our qualified pharmacists and delivered discreetly to your door, with ongoing support available if you have questions or concerns.

Remember, you should never stop or change your abiraterone or any other prescribed medicine without speaking to your oncologist or GP. If you are unsure whether tadalafil is right for you, or if you have new or worsening erectile dysfunction, book an appointment with your doctor. Erectile dysfunction can be an early warning sign of cardiovascular disease or diabetes, so it is important to have a full medical review [1][2].

Confidential, Expert Care

We understand that discussing erectile dysfunction can feel sensitive, especially when you are managing a serious condition like prostate cancer. Our service is designed to be discreet, supportive, and led by experienced healthcare professionals. Every consultation is confidential, and our team is here to answer your questions and ensure you receive safe, effective treatment tailored to your needs.

When to get urgent help

• Erection lasting more than 4 hours (priapism)—go to A&E immediately to prevent permanent damage
• Sudden loss of vision in one or both eyes—stop tadalafil and seek urgent medical help
• Sudden decrease or loss of hearing, possibly with ringing in the ears or dizziness—stop tadalafil and see a doctor urgently
• Chest pain during sex—stop activity, do not use GTN spray, sit or lie down, and call 999
• Severe dizziness, fainting, or signs of very low blood pressure—seek same-day medical advice

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.